Easy JLPT NewsGrammar
Every JLPT N5 and N4 grammar point with a plain-English explanation, example sentences, common mistakes and a three-question check. Also available in Vietnamese.
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Topic marker は (wa): 'as for ...'
は shows the topic of the sentence: the thing you are going to talk about. The important information comes after は. The topic is usually something the listener already knows or can see. Once the topic is clear, Japanese speakers usually do not repeat it in the next sentences.
A is B (polite)
AはBです says that A is B, or that A belongs to the group B. は marks the topic, and です makes the sentence polite. です does not change with the person: 'I am', 'you are' and 'she is' are all です. Use it when you talk to people you do not know well, to teachers, and at work.
is not / am not / are not (polite negative of です)
This is the polite negative form of です. It is used after nouns and な-adjectives to say that something is not so. じゃありません is common in speaking. ではありません sounds more formal and is common in writing. Verbs and い-adjectives make their negative forms in a different way.
Question marker か
Adding か to the end of a polite sentence turns it into a question. The voice usually rises on か. In Japanese writing, a question with か normally ends with 「。」, not with a question mark. In casual speech between friends, か is usually dropped and only the voice rises (行く？).
Also / too (and 'not ... either')
も means 'also' or 'too'. It shows that what was true for one thing is true for another thing as well. も comes right after the word that is 'added', not at the end of the sentence like English 'too'. In a negative sentence it means 'not ... either'.
の: possession and noun + noun ('A's B', 'B of A')
の joins two nouns. The first noun explains the second noun, so the main noun always comes last. This order is the same as English 'my book' but the opposite of 'a book of mine', and the opposite of Vietnamese. の is often translated as ''s' or 'of', but its meaning is wider: it only says that the first noun tells us something about the second.
This / that / that over there (things)
These words point at things without saying their names. Which one you use depends on where the thing is: near you (これ), near the person you are talking to (それ), or far from both of you (あれ). Because of this, the word often changes between a question and its answer: a thing that is それ for you is これ for the person holding it. In conversation, それ can also point to what the other person has just said (それはいいですね).
This / that / that ... over there + noun
この, その and あの come before a noun and show which one you mean: 'this book', 'that book (near you)', 'that book over there'. The rule for near and far is the same as for これ / それ / あれ. In Vietnamese the word 'này / đó / kia' comes after the noun, but in Japanese この / その / あの always come before it.
Here / there / over there (places and directions)
ここ, そこ and あそこ point at places, in the same way that これ, それ and あれ point at things. Note that the far form is あそこ, not あこ. こちら, そちら and あちら first mean a direction, but shop staff and office workers also use them as polite words for 'here', 'there' and 'over there'. On the phone, そちら often means 'the place where you are'.
Basic question words: what, who, where, when, how much, how many
Question words ask for a piece of information, so the answer is the information itself, not はい or いいえ. Japanese does not move the question word to the front of the sentence. It stays where the answer would be: これは本です → これは何ですか. The answer normally uses the same particle as the question: だれが来ましたか — 田中さんが来ました.
Which one / which + noun / which of the two
These are the question words of the こ・そ・あ・ど family: これ → どれ, この → どの, こちら → どちら. They ask the listener to choose from a group that both people can see or already know. The answer often uses a こ・そ・あ word: どれですか — これです.
Please give me ... / I'll have ...
〜をください is used to ask someone to give you a thing. It is the basic way to order in a restaurant and to buy things in a shop or at a ticket window. It is polite enough for shops and restaurants. It can also be used for things you cannot touch, such as time (時間をください).
Verb groups: Group I (godan), Group II (ichidan), Group III (irregular)
Japanese verbs are divided into three groups by the way they change form. You need to know a verb's group to make the て-form, ない-form, dictionary form and た-form correctly. In Group I the sound before ます changes (書きます → 書く, 書かない, 書いて). In Group II you only take off ます or る and add the new ending (食べます → 食べる, 食べない, 食べて). Group III has two irregular verbs, する and 来る, and you simply memorize their forms.
Polite verb form: 〜ます / 〜ません / 〜ました / 〜ませんでした
ます makes a verb polite. Use it with people you do not know well, with teachers, at work and in shops. 〜ます is used for habits and for the future (Japanese has no separate future form), 〜ました is used for the past, and 〜ません and 〜ませんでした are the negative forms. With family and close friends, people usually use the plain form (行く, 行かない) instead.
に: at / on / in (a point in time)
に after a time word shows the point in time when an action happens, like 'at', 'on' or 'in' in English. It is needed after clock times, dates, months and years. Words like 今日, あした and 毎日 already work as adverbs, so they take no particle.
from ... to / until ...
から marks the starting point and まで marks the end point. They are used for time (from 9 o'clock until 5 o'clock) and for place (from home to the station). You do not have to use both: use only から when you talk about the start, and only まで when you talk about the end.
と: and (listing all the items)
と joins two or more nouns and means 'and'. It tells the listener that the list is complete: パンと卵を食べました means you ate bread and eggs, and that is all you are listing. If you want to give only some examples, use や instead.
へ: to / toward (direction of movement)
へ shows the direction or the place that someone moves toward. At N5 it is used mostly with 行きます (go), 来ます (come) and 帰ります (return). With these verbs you can also use に, and the meaning is almost the same.
で: by / with / in (means, tool, material, language)
で shows the means used to do something: how you travel, what tool you use, what something is made from, or what language you use. In English it becomes 'by', 'with', 'from' or 'in'; in every case で answers the question 'using what?'.
と: together with (a person)
と after a person shows who you do something with. 友だちと映画を見ました means 'I watched a movie with a friend'. Adding 一緒に makes 'together' clearer, but the meaning is the same without it.
を: direct object marker
を marks the direct object: the thing that the action is done to. In パンを食べます, パン is what you eat. Japanese word order is object + を + verb, so the verb comes last.
で: at / in (place where an action happens)
で after a place shows where an action happens. 図書館で勉強します means 'I study at the library': the library is the place of the activity. English uses 'at', 'in' or 'on' here, but Japanese chooses the particle by the verb: an action takes で.
Won't you ...? / Would you like to ...? (invitation)
〜ませんか is a polite way to invite someone to do something with you, or to offer something. The form is negative, but the meaning is not negative: 行きませんか means 'Would you like to go?'. Because it asks what the listener wants, it sounds soft and leaves room to say no.
Let's ...
〜ましょう means 'let's ...'. The speaker suggests doing something together with the listener and pulls the listener along. It is also the usual way to say yes to an invitation. At N5 the action is normally done by the speaker and the listener together; it is not used to state the speaker's own plan.
Sentence-final ne: '..., isn't it?' / '..., right?' (agreement, confirmation)
ね is put at the end of a sentence when the speaker thinks the listener knows or feels the same thing. It has two main uses: asking for agreement ('It's hot, isn't it?') and checking that something is correct ('The test is tomorrow, right?'). It makes the sentence sound soft and friendly. そうですね is a very common way to agree.
Sentence-final yo: '..., you know' (telling new information)
よ is put at the end of a sentence when the speaker tells the listener something the listener does not know or has not noticed. It is used to give information, advice, or a warning, or to tell someone not to worry. It means something like 'you know' or 'I'm telling you', but it is often not translated into English.
ni: where something is, where you arrive, who receives the action
This に marks a point. It shows the place where a thing or person exists, the place where a movement ends, or the person an action is directed to. The place where you do an action (eat, study, work) takes で, not に. The に for time (7時に) and for purpose (買い物に行きます) are explained on their own pages.
to give / to receive (things)
あげます means 'give' and もらいます means 'receive'. The subject of あげます is the giver, and the subject of もらいます is the receiver. あげます is not used when the receiver is 'me': for 'someone gives me something', Japanese uses くれます, or you make yourself the subject with もらいます. This page is about giving and receiving things; doing an action for someone (〜てあげる / 〜てもらう) is N4.
already / not yet, still
もう shows that something has changed or finished earlier than now: 'already'. まだ shows that a situation has not changed: 'still' in a positive sentence, and 'not yet' in a negative sentence. To the question もう〜ましたか, the short negative answer at N5 is いいえ、まだです. With a negative, もう means 'not any more' (もう時間がありません).
i-adjectives and their conjugation
An い-adjective is an adjective whose dictionary form ends in い, such as 高い, おいしい or 忙しい. The adjective itself changes to show negative and past, so です after it never changes to でした or じゃありません. です only makes the sentence polite. An い-adjective can also go directly before a noun to describe it.
na-adjectives and their conjugation
な-adjectives are adjectives such as 静か, 元気, 便利, 有名 and 好き. They are called な-adjectives because they need な when they come before a noun. The word itself never changes; negative and past are shown by です, in the same way as with nouns. ではありません is more formal than じゃありません.
was / was not (past of です)
でした is the past form of です. It is used after nouns and な-adjectives to say what something was or how it was. The past negative is じゃありませんでした: you add でした to the negative じゃありません. Verbs and い-adjectives have their own past forms (〜ました, 〜かったです), so でした is not used with them.
not very / not much / not often
あまり with a negative means that the degree, amount or frequency is low: 'not very', 'not much', 'not often'. It does not mean zero. At N5, always use あまり together with a negative form. It also makes a negative answer softer: あまり好きじゃありません is a polite way to say that you do not like something. In casual speech it is often pronounced あんまり.
not at all
ぜんぜん with a negative makes the negative complete: 'not at all', 'never', 'nothing'. It is stronger than あまり〜ない. It is also used with a few words that already have a negative meaning, such as ぜんぜん違います (completely different) and ぜんぜんだめです (no good at all). In casual conversation people sometimes say things like ぜんぜん大丈夫, but in textbooks and on the JLPT ぜんぜん goes with a negative.
how / what kind of
どう means 'how'. 〜はどうですか asks for someone's impression or about the condition of something, and the answer is usually an adjective (おもしろいです, 大変でした). どうですか is also used to offer or suggest something: お茶はどうですか (How about some tea?). どんな means 'what kind of' and asks for a description of the noun after it; the answer is usually adjective + noun (親切な人です).
ga: but / soft introduction
This が joins two sentences into one. Its first use is 'but': the second part is in contrast with the first part. Its second use is a soft introduction: in すみませんが or 田中ですが, が does not mean 'but'. It only prepares the listener for the question or request that follows. This が comes after a whole sentence, so it is different from the subject particle が that comes after a noun.
Contrastive は: 'A is ..., but B is ...'
は does more than mark the topic. It can set one thing against another: 'A is like this, but B is different.' In a negative sentence, は often marks the thing you say 'no' about, and it hints that something else may be different: お酒は飲みません suggests 'I don't drink alcohol, but I may drink other things.'
が: subject marker
が marks the subject: the person or thing that does the action or is in the state. It is used when the subject is new or is the important information, for example when a question word is the subject (だれが来ましたか) and in the answer (田中さんが来ました). It is also used when you describe something you see or notice right now (雨が降っています), and when you say that something exists (駅の前に銀行があります).
が with 好き / 上手 / わかる / ある (the thing a state is about)
Words like 好き (like), きらい (dislike), 上手 (good at), 下手 (bad at), わかる (understand) and ある (have) do not show an action. They show a state: a feeling, a skill, or having something. The thing that the state is about takes が, not を. In English this thing is the object ('I like cats'), so learners often want to use を, but Japanese says わたしは猫が好きです.
because / so
から comes at the end of the reason and joins it to the result: 'reason から、result'. Note that the order is the opposite of English 'result because reason'. The result part can be a fact, but it can also be a request, an invitation or your own plan: 暑いですから、窓を開けてください. から states the reason clearly and directly, so it is very common in everyday speech.
why
どうして and なぜ both ask for a reason: 'why'. They usually come at the beginning of the question, or right after the topic. The answer gives the reason with から, most often in the form 〜からです. どうして is the usual word in conversation, and なぜ sounds a little more formal.
there is / to have (あります for things, います for people and animals)
あります and います both mean 'there is' or 'to be (somewhere)'. Use います for people and animals, which are alive and move by themselves. Use あります for everything else: things, plants, buildings, and also time, money, plans and events. The place takes に, and the thing that exists takes が. The same verbs also mean 'to have': わたしは兄がいます (I have an older brother), 今日は時間があります (I have time today).
position words: on, under, in front of, behind, in, outside, next to, between
Japanese position words are nouns. You name the reference point first and join the position word to it with の: 机の上 is 'the top of the desk', that is, 'on the desk'. The order is the opposite of English and Vietnamese, where 'on' comes before 'the desk'. After the position word, you add a particle such as に or で, just as you do after any place noun.
nothing / nobody / nowhere (not ... anything)
A question word + も with a negative verb means 'not any' or 'none at all': 何も食べません (I don't eat anything), だれも来ませんでした (Nobody came), どこへも行きません (I'm not going anywhere). The word with も does not make the sentence negative by itself, so the verb must be in the negative form. English often uses one negative word ('nothing', 'nobody'), but Japanese needs も and a negative verb together.
something / someone / somewhere / someday
When か is added to a question word, the word stops being a question and means 'some-': 何 (what) becomes 何か (something), だれ (who) becomes だれか (someone). You use it when you do not know, or do not need to say, exactly what, who, where or when. In a question it means 'anything / anyone / anywhere', and the question is a yes/no question: 何か食べましたか (Did you eat anything?) is answered with はい or いいえ.
A or B
Between two nouns, か means 'or': one of the two, not both. 土曜日か日曜日 is 'Saturday or Sunday'. To ask someone to choose, Japanese repeats the whole question: これは「り」ですか、「い」ですか (Is this り or い?). The listener answers with the correct half: 「り」です.
A, B, and so on (partial listing)
や lists two or three things as examples and tells the listener that the list is not complete: there are other things too. など ('and so on') can be added after the last noun to make this meaning clearer. Use や when you cannot or do not need to name everything. When you name everything, use と.
counters and where to put a quantity in a sentence
In Japanese you cannot count with a number alone. You add a counter that matches the kind of thing you count, a little like 'two sheets of paper' in English. The quantity usually comes after the noun and its particle, right before the verb: 切手を二枚買います. Some counters change their sound with some numbers, so the readings must be learned: 一本 is いっぽん, 三本 is さんぼん, 六本 is ろっぽん, and one person and two people are ひとり and ふたり.
... times per (period)
This pattern tells how often something happens in a fixed period: 1週間に3回 means 'three times a week'. The particle に marks the period that the count is measured in. To ask about frequency, use 何回: 1か月に何回〜か. Short forms such as 週に1回 and 月に2回 are also very common.
only / just
だけ limits something to one thing or one amount: 'only this, nothing else'. It is a neutral word, so it does not by itself show that the speaker feels the amount is too small. The sentence can be positive or negative: リンさんだけ来ました (only Lin came) and リンさんだけ来ませんでした (only Lin did not come) are both correct, but the meaning is different.
about / approximately (amount)
ぐらい / くらい comes after an amount and shows that the number is not exact: 20分ぐらい is 'about 20 minutes'. It is used for how much, how many and how long. For an approximate point in time (about 3 o'clock, around April), the standard word is ごろ. When you say how long an action lasts (2時間ぐらい勉強します), the length of time is used without the particle に.
around (a point in time)
ごろ comes after a point in time and means 'at about' or 'around': 6時ごろ is 'around six o'clock'. Use it when you do not know or do not want to say the exact time. It is only for points in time. For an approximate amount or length of time (about two hours, about ten people), use ぐらい.
each / ... at a time
ずつ shows that the same amount is given to each person or thing, or that the same amount is repeated each time. みんなに2つずつあげます means 'I give two to each person', and 毎日5つずつ覚えます means 'I learn five every day'. With 1人 or 1つ it often means 'one at a time': 1人ずつ入ってください. 少しずつ means 'little by little'.
in the middle of / within / all through
中 is added to a noun and has two readings. Read ちゅう, it means that an action is going on now (電話中 = on the phone) or that something happens at some point within a period (今週中に = by the end of this week). Read じゅう, it means the whole of a time or place with nothing left out: 一日中 is 'all day long' and 日本中 is 'all over Japan'. The reading is fixed for each word, so learn the common words one by one.
A is more ... than B
より means 'than' and marks the thing you compare with. In A は B より大きいです, A is the topic and A is the bigger one; B is only the standard. Japanese adjectives have no comparative form like 'bigger' or 'more quiet', so より alone shows the comparison. より always comes after B, the opposite of English 'than B' and Vietnamese 'hơn B', where the word comes before B.
which is more ..., A or B? / A is more ...
Use this pair of patterns to compare exactly two things. The question lists both things with と and asks どちらが ('which one'). どちら is used for things, people, places and times alike when there are two. The answer marks the chosen side with のほうが ('the ... side is more ...'). In both the question and the answer the particle is が, because the point of the sentence is which one.
the most ... (superlative)
一番 means 'number one' and makes the superlative: 一番好きです is 'I like it the most'. Use it when you choose from three or more things or from a whole group. The group is marked with で ('among', 'in'), and the thing that comes first is marked with が. In questions, choose the question word by what you are asking about: 何 for things, だれ for people, どこ for places, いつ for times, and どれ when you choose from a short list that was just named.
to want (something)
ほしい says that the speaker wants to have a thing. It is an い-adjective, not a verb, so the thing you want takes が, not を. In a statement it shows the speaker's own wish, and in a question it asks about the listener's wish. For another person's wish, Japanese usually adds something such as 〜と言っています. For wanting to do an action, use verb + たい, not ほしい.
to want to do
たい is added to a verb to say that the speaker wants to do that action: 日本へ行きたいです is 'I want to go to Japan'. In a statement it shows the speaker's own wish, and in a question it asks about the listener's wish. For another person's wish, Japanese usually adds something such as 〜と言っています. For wanting a thing, not an action, use noun + がほしい.
to go / come in order to do
This pattern tells the purpose of going, coming or returning somewhere: 映画を見に行きます is 'I am going (somewhere) to see a movie'. The purpose is a verb ます-stem or an action noun, followed by に. The main verb is a verb of movement such as 行く, 来る or 帰る, so the place takes へ or に, not で. Tense, negation and invitations are all shown on the movement verb at the end.
How to do / way of doing
Adding 方 (かた) to the ます-stem of a verb makes a noun that means 'how to do' or 'the way of doing' something. Because the new word is a noun, the thing in front of it is joined with の, not を. You can then use it like any noun: 〜方を教えてください, 〜方がわかりません, 〜方を知っています.
を: through / along / out of (path and point of departure)
を does not only mark the object of an action. With verbs of movement, it marks the place you move through or along, such as a park, a road, a bridge or the sky. With 出る and 降りる, it marks the place or vehicle you leave. In both uses the noun before を is a place, not a thing that receives the action.
How to make the て-form
The て-form is a verb form that connects a verb to what comes next. It has no tense of its own; the end of the sentence shows the tense and the politeness. At N5 you need it for 〜てください (requests), 〜ています (actions in progress and states), 〜て、〜 (actions in order) and 〜てから (after doing). First check which group the verb belongs to, and then apply the sound change for that group.
Please do ...
〜てください is used to politely ask or tell someone to do something. You hear it in requests (教えてください), in instructions from teachers, doctors and staff (ここに書いてください), and when you kindly invite someone to do something for their own good (どうぞ、座ってください). It is polite, but it is still a direct instruction, so with a boss or a stranger people often choose a softer form such as 〜てくださいませんか (N4).
To be doing (action in progress)
With verbs for actions that take some time, such as 食べる, 読む, 書く, 話す and 降る, 〜ています shows that the action is going on right now. It is often used with 今 and answers the question 今、何をしていますか. The past form 〜ていました shows what was going on at a certain time in the past. With verbs that show a quick change, such as 結婚する or 知る, 〜ています usually shows a state instead; see 〜ています（結果の状態・習慣・職業）.
Shall I ...? (offering to do something)
〜ましょうか is used when the speaker offers to do something for the listener: 'Shall I ...?'. The speaker sees that the listener needs help and asks before acting. To accept, say ええ、お願いします or すみません、お願いします. To refuse politely, say いいえ、大丈夫です or いいえ、けっこうです. The same form can also be a soft 'Shall we ...?' when both people do the action together; see the comparison with 〜ましょう below.
Resulting state / habit / job (is married, lives in, knows, works at)
〜ています does not only mean 'is doing'. (1) With verbs that show a quick change, such as 結婚する, 知る, 持つ, 着る and かぶる, it shows the state that continues after the change: 結婚しています (is married), 持っています (has), 帽子をかぶっています (is wearing a hat). 住んでいます (lives in) is also used this way. (2) It shows a habit that is repeated over a period of time: 毎朝、走っています. (3) It tells a person's job or school: 銀行で働いています, 大学で勉強しています.
Do A, then B (linking actions with the て-form)
The て-form links actions that happen one after another, in the order they are said: 'do A, (then B,) and then C'. The て-form itself has no tense, so the last verb tells you whether the whole sentence is past, present, a request and so on. Because the order has meaning, 歯を磨いて、朝ごはんを食べます means you brush your teeth first.
After doing ... / since doing ...
A てから B means 'after doing A, do B'. It makes the order clear: A comes first, and B happens only after A is done. It is often used for the right order of steps (手を洗ってから、食べます). It can also mean 'since', for something that has continued from the time of A: 日本へ来てから、毎日日本語を勉強しています.
Linking adjectives and nouns: ... and ... (くて / で)
This is the て-form of adjectives and nouns. It joins two or more descriptions in one sentence, like 'and': この部屋は広くて、明るいです. The descriptions usually point in the same direction (both good or both bad). When they are opposite, が (but) is used instead. The first part can also give a light reason for the second part, as in 暑くて、眠れません; that use is studied at N4.
As for A, its B is ... (は〜が sentences)
This sentence pattern first gives a topic with は, and then describes one part or one side of that topic with が. 象は鼻が長いです is, word for word, 'As for elephants, the nose is long', that is, 'Elephants have long noses'. Japanese uses this pattern where English uses 'have' or 'has' for the features of people, places and things, and also for how your body feels: わたしは頭が痛いです (I have a headache).
How to make the ない-form (plain negative)
The ない-form is the plain negative form of a verb. 行かない means the same as 行きません, but it is the plain style used with friends and family. It is also used inside longer patterns. At N5 you need it for 〜ないでください (please don't) and for plain-form sentences such as 〜ないと思います. At N4 it is the base of 〜なければなりません, 〜なくてもいいです and 〜ないほうがいいです. ない changes like an い-adjective, so the past is 〜なかった.
Please don't ...
Use this pattern to ask or tell someone not to do something. It is the negative of 〜てください. You often see it in rules and warnings, such as in a museum or a hospital. It is also used kindly, to show you care, as in 心配しないでください (Please don't worry).
Dictionary form (plain non-past): how to make it
The dictionary form is the form of a verb that you find in a dictionary. It is the plain (casual) form of 〜ます, so it shows the present, the future, or a habit. You use it at the end of a sentence in casual speech. You also need it before many grammar patterns, such as 〜ことができます, 〜ことです and 〜まえに.
Can / be able to
This pattern says that someone can do something. It has two uses. One is a person's ability or skill, as in 漢字を読むことができます (I can read kanji). The other is that something is possible in a place or situation, as in ここでカードを使うことができます (You can use a card here). The thing you can do is marked with が.
こと: turning a verb into a noun ('doing ...')
こと after a verb in the dictionary form turns the verb phrase into a noun, like 'reading books' or 'to read books' in English. A verb cannot come directly before です, が or は, so you add こと first. The most common N5 use is to talk about hobbies and dreams: わたしの趣味は〜ことです.
Before doing / before ...
A まえに B means 'before A, B'. B is the action that happens first, and A happens later. The tense of the whole sentence is shown only at the end of the sentence, so the verb before まえに does not change. With a length of time, 〜まえに means '... ago'.
Ta-form (plain past): how to make it
The た-form is the plain (casual) form of 〜ました. It shows the past, or that something is finished. You use it at the end of a sentence in casual speech. You also need it before patterns such as 〜たあとで, and before a noun, as in 昨日買った本 (the book I bought yesterday). The sound changes are the same as in the て-form, so if you know the て-form, you already know the た-form.
After doing / after ...
A たあとで B means 'after A, B'. A happens first and is finished, and then B happens. The た here does not mean that the whole sentence is in the past. The tense of the sentence is shown only at the end. It is the partner of 〜まえに (before).
To become ... / to get ...
なる means 'to become'. This pattern shows that a person, a thing or a situation changes into a new state. The change happens by itself or over time, and the sentence does not say who caused it. 〜なりました says the change has already happened, and 〜なります is for a change that will come or that always comes.
To make something ... (change it on purpose)
This pattern shows that someone changes a thing into a new state on purpose. The thing that is changed is marked with を. It is the partner of 〜くなる / 〜になる, where the thing changes and nobody is named as the cause. It is often used in requests, such as 小さくしてください and きれいにしてください. 静かにする is a set phrase that means 'to be quiet'.
Adjectives used as adverbs (hayaku, kirei ni)
An adjective describes a noun, but with 〜く or 〜に it can describe a verb. It tells you how an action is done, like 'early', 'neatly' or 'quietly' in English. The 〜く / 〜に word usually comes before the verb, and other words such as the object can come between them. よく, from いい, means 'well', and it can also mean 'often'.
Plain form of verbs, adjectives and nouns
The plain form is the short form that matches the polite form (〜ます / 〜です). It has two jobs. First, it ends sentences in casual speech with friends and family. Second, it is used inside a sentence before patterns such as 〜と思います, 〜と言いました and 〜から, and before a noun (before a noun, 静かだ becomes 静かな and 雨だ becomes 雨の). In the second job the sentence is still polite, because politeness is decided by the end of the sentence.
Casual speech (plain style)
Plain style is the way you talk to friends, family and people younger than you. The meaning is the same as polite style (〜ます / 〜です), but it sounds close and relaxed. To teachers, customers, people you meet for the first time and people above you at work, use polite style. If you use plain style with them, it can sound rude. Plain style is also used in writing such as diaries.
I think that ...
Use と思います to give your opinion or your guess. The part before と is what you think, and it is written in the plain form. It sounds softer than a simple です／ます sentence. To say "I don't think ...", Japanese usually makes the inside negative: 来ないと思います is more common than 来ると思いません. In a statement, と思います normally shows the speaker's own thought; for another person's opinion, と思っています is usually used.
to say that ... (quotation)
The particle と marks the words that someone says. You can repeat the exact words in 「」, or report the content in the plain form without 「」. The tense inside the quote stays the same as in the original words, even when 言いました is in the past. The same pattern is used to tell what something is called: これは日本語で「かさ」と言います.
Noun-modifying clauses (relative clauses)
In Japanese, a whole clause can describe a noun, and it always comes before that noun: 母が作ったケーキ = the cake that my mother made. English and Vietnamese put this part after the noun, so the word order is the opposite. The clause is in the plain form, even in a polite sentence; only the end of the whole sentence becomes です／ます. The noun with its clause works like any noun, so it can be followed by は, が, を, に and so on.
の: the ... one / mine (の in place of a noun)
This の takes the place of a noun that both people already understand, like "one" in "the red one" or like "mine." It lets you avoid repeating the same noun: このかさはわたしのです = This umbrella is mine. It is mostly used for things. For people it can sound rude, so 人 or 方 is usually used instead.
When ... / at the time of ...
〜とき tells the time when the main action or state happens: A とき、B = when A, B. The tense of the whole sentence is shown only at the end of the sentence. With action verbs, the form before とき shows the order of the two actions. Dictionary form + とき means B happens before A is finished (before or during A); た-form + とき means B happens after A is finished. This difference matters most with verbs of movement such as 行く, 来る and 帰る.
to give (to me / my family)
くれます means "give" when someone gives something to me, or to a person on my side such as my family. The giver is the subject, and it is another person, not the speaker. Japanese has two verbs for "give": あげます is for giving to other people, and くれます is for giving to me. くれます often carries a feeling of thanks. In a question, you can also use it for something given to the listener: だれがくれましたか (Who gave it to you?).