B2 Expressions & Patterns 11 min read 简单

给出直接建议 (~koto da)

当你想要给出坚定的、专家式的专业建议时，用 «ことだ» 就对了！记住它是给别人的 «建议»，是通往成功的 «秘诀»。
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Grammar Rule in 30 Seconds

Use 'Verb (dictionary form) + koto da' to give strong, objective advice or express a necessary action.

  • Use dictionary form verbs: {寝る|ねる}ことだ (You should sleep).
  • It sounds authoritative, so avoid using it with superiors.
  • It implies a logical necessity or a 'best course of action' scenario.
Verb (Dictionary Form) + ことだ

Overview

~ことだ (koto da) is a Japanese grammar pattern used to deliver strong, direct advice or to state a fundamental principle for success. It elevates a suggestion to the level of an essential truth or a rule of thumb, implying that the speaker has the experience or authority to make such a declaration. Unlike softer advisory forms like ~方がいい (hou ga ii), which merely presents a better option, ~ことだ asserts that a specific action is the correct and necessary course to take.
At its core, ~ことだ is used to say,
The key thing is to do X,
or "What's important is that you do X.
It frames the advice not as a personal opinion, but as an objective principle. Imagine a seasoned chef telling a novice, 毎日練習(まいにちれんしゅう)することだ (Mainichi renshuu suru koto da –
The thing to do is practice every day"). The chef isn't just suggesting it; they are stating a non-negotiable tenet of culinary mastery.
This pattern is therefore common in contexts of mentorship, instruction, and expert guidance, where one person is imparting established wisdom to another.
Because of its authoritative tone, using ~ことだ requires careful consideration of the social context. It is most appropriate when speaking to someone of equal or lower status who is seeking guidance, or in impersonal contexts like instruction manuals and articles. Misusing it can sound condescending or arrogant, making it a powerful but delicate tool for B2-level learners to master.

How This Grammar Works

To understand ~ことだ, you must first grasp the function of its two components: the nominalizer こと (koto) and the assertive copula だ (da).
  1. 1The Nominalizer こと (koto): In Japanese, こと turns entire verb phrases into nouns. Critically, こと nominalizes abstract concepts, intangible events, facts, or matters. This is distinct from the nominalizer の (no), which tends to refer to a concrete, observable action. By using こと, the action (e.g., practicing every day) is transformed into an abstract principle (
    the act/matter of practicing every day
    ). This abstraction is key; it shifts the focus from a single action to a general rule.
  1. 1The Copula だ (da): This is the plain form of to be. When you append だ, you are making a strong, declarative statement:
    It is [the nominalized principle].
    The sentence 毎日練習(まいにちれんしゅう)することだ literally translates to
    It is the matter of practicing every day.
    This structure frames the advice as an established fact rather than a subjective suggestion. The speaker is essentially defining the solution or the correct path forward.
Consider the nuance: if you say 休(やす)んだ方(ほう)がいい (Yasunda hou ga ii), you're saying, "The 'resting' option is better." It's a comparison. But when you say 休(やす)むことだ (Yasumu koto da), you're defining the situation:
The required action is to rest.
There is no comparison; it's a definitive statement. This is why it feels so much stronger.
The grammar itself packages the advice as an irrefutable principle learned through experience.

Formation Pattern

1
~ことだ attaches to verbs in their plain form (dictionary or ない-form). The formation is simple and direct, which mirrors the directness of the advice itself.
2
Core Structure:
3
Positive Advice (Do this): Verb (Dictionary Form) + ことだ
4
Negative Advice (Don't do this): Verb (ない-form) + ことだ
5
For added politeness or emphasis in spoken language, the copula だ can be changed to です or have particles like よ appended. In formal writing, である is also used.
6
Formation and Politeness Table:
7
| Verb Type | Form | Example Sentence | Pitch Accent (Std.) | Nuance & Use Case |
8
| :------------ | :----------------- | :---------------------------------------------------------------------------- | :------------------ | :------------------------------------------------------------------------------------------------------------ |
9
| Positive | Dictionary + ことだ | 成功(せいこう)したければ、諦(あきら)めないことだ。 (Seikou shitakereba, akiramenai koto da.) | HLLLHH-LL | Strong, direct principle. (If you want to succeed, the key is not to give up.) Standard, plain form. |
10
| Negative | ない-form + ことだ | 健康(けんこう)のために、無理(むり)をしないことだ。 (Kenkou no tame ni, muri o shinai koto da.) | HLHHLLH-LL | Strong, direct prohibition. (For your health, the important thing is not to overdo it.) |
11
| Polite Spoken | Dictionary + ことです | まず(まず)は基本(きほん)を覚(おぼ)えることです。 (Mazu wa kihon o oboeru koto desu.) | HLLLHLL-LH | Firm but polite. Softer than ことだ, suitable for addressing clients or students respectfully. |
12
| Emphatic | Dictionary + ことだよ | 大丈夫(だいじょうぶ)、とにかく続(つづ)けることだよ。 (Daijoubu, tonikaku tsuzukeru koto da yo.) | HLLLLH-LL-L | Softer, more encouraging. The よ particle adds a nuance of "I'm telling you / you know." Friendly advice. |
13
| Formal Written | Dictionary + ことである | 問題解決(もんだいかいけつ)には多角的(たかくてき)な視点(してん)を持(も)つことである。 (Mondaikaketsu ni wa takakuteki na shiten o motsu koto de aru.) | — | Formal, academic, or official. Used in papers, reports, and official documents to state a principle. |
14
*Pitch Accent Note:* The standard pitch for こと is HLL (koꜜto). The final copula (だ, です, etc.) typically follows this with a low pitch. Thus, ことだ is usually HLLL (koꜜto da). Variations exist, but this is a reliable starting point.

When To Use It

Deploying ~ことだ effectively hinges on recognizing the right social and situational contexts. Its use is justified when the speaker holds a position of experience or authority relative to the listener or topic.
  • Giving Foundational Rules for a Skill: When teaching a skill like a sport, a musical instrument, or a language, ~ことだ is perfect for stating the golden rules. It establishes the non-negotiable actions required for improvement.
  • 外国語(がいこくご)を話(はな)せるようになりたければ、間違(まちが)いを恐(おそ)れないことだ。 (Gaikokugo o hanaseru you ni naritakereba, machigai o osorenai koto da.) –
    If you want to be able to speak a foreign language, the most important thing is not to fear mistakes.
  • Providing Life Advice or General Wisdom: This pattern is frequently used by mentors, parents, or seniors when imparting wisdom gained through life experience. It frames the advice as a universal truth.
  • 若(わか)いうちに、できるだけ多(おお)くの経験(けいけん)を積(つ)んでおくことだ。 (Wakai uchi ni, dekiru dake ooku no keiken o tsunde oku koto da.) – "While you're young, you should build up as much experience as possible."
  • Stating a Necessary Step in a Process: In instructions, guides, or when explaining a strategy, ~ことだ highlights a critical or prerequisite step. It clarifies that this action is the key to moving forward.
  • データ(でーた)が消(き)えないように、こまめに保存(ほぞん)することだ。 (Deeta ga kienai you ni, komame ni hozon suru koto da.) – "To ensure your data isn't lost, the thing to do is save frequently."
  • Self-Guidance or Internal Monologue: You can also use ~ことだ to give yourself a firm reminder or to steel your resolve. It acts as a personal mantra to reinforce a principle you believe in.
  • *(Stressed about a big project)* 焦(あせ)らない、焦(あせ)らない。一(ひと)つずつ確実(かくじつ)に終(お)わらせることだ。 (Aseranai, aseranai. Hitotsu zutsu kakujitsu ni owaraseru koto da.) – "Don't panic. The key is to finish each task reliably, one by one."
  • Impersonal Written Contexts: ~ことだ is very common in self-help books, business articles, and online guides. The impersonal nature of writing makes the authoritative tone feel instructional rather than bossy.

Common Mistakes

Due to its strong nuance, learners often misuse ~ことだ, leading to socially awkward or grammatically incorrect sentences. Pay close attention to these distinctions.
  • Using with Superiors (目上|めうえ): This is the most critical mistake. Never use ~ことだ to advise a boss, teacher, elder, or anyone of higher status. It sounds incredibly arrogant, as if you are lecturing them. For superiors, use polite, suggestive forms.
  • Incorrect: 部長(ぶちょう)、もっと詳(くわ)しく説明(せつめい)することです。 (Buchou, motto kuwashiku setsumei suru koto desu.)
  • Correct: 部長(ぶちょう)、もしよろしければ、もう少し詳(くわ)しくご説明(せつめい)いただけますでしょうか。 (Buchou, moshi yoroshikereba, mou sukoshi kuwashiku go-setsumei itadakemasu deshou ka.) – "Boss, if it's alright, could I have you explain in a bit more detail?"
  • Confusing with ~ことにしている (Personal Habit): These two are easily mixed up but mean different things. ~ことだ is advice for others; ~ことにしている is a personal rule you follow.
| Grammar | Meaning & Nuance | Example |
| :-------------------- | :---------------------------------------------- | :------------------------------------------------------------------------------------------------------ |
| ~ことだ | A general principle or advice for others. | 健康(けんこう)のためには野菜(やさい)を食(た)べることだ。 (Kenkou no tame ni wa yasai o taberu koto da.) –
For health, the key is to eat vegetables.
|
| ~ことにしている | A personal rule or habit I have decided on. | 私(わたし)は健康(けんこう)のために野菜(やさい)を食(た)べることにしている。 (Watashi wa kenkou no tame ni yasai o taberu koto ni shite iru.) –
I make it a rule to eat vegetables for my health.
|
  • Confusing with ~べきだ (Moral/Social Obligation): Both express strong recommendations, but the basis for the advice differs. ~べきだ is based on morality, logic, or social convention (should), while ~ことだ is based on experience or strategy for achieving a goal (
    the key is to
    ).
| Grammar | Basis for Advice | Example |
| :----------- | :---------------------------------------------------- | :----------------------------------------------------------------------------------------- |
| ~ことだ | Pragmatic/Strategic: The best way to get a result. | 試験(しけん)に合格(ごうかく)したいなら、毎日勉強(まいにちべんきょう)することだ。 (Shiken ni goukaku shitai nara, mainichi benkyou suru koto da.) –
If you want to pass the test, the key is to study every day.
|
| ~べきだ | Moral/Logical: The proper or right thing to do. | 学生(がくせい)は毎日勉強(まいにちべんきょう)するべきだ。 (Gakusei wa mainichi benkyou suru beki da.) –
Students should study every day.
(It's their duty/the proper thing for them to do.) |
  • Using for Past Regrets: ~ことだ is forward-looking. It cannot be used in the past tense to express regret. For that, use ~べきだった (beki datta) or ~すればよかった (sureba yokatta).
  • Incorrect: あの時(あのとき)、彼女(かのじょ)に謝(あやま)ることだった。 (Ano toki, kanojo ni ayamaru koto datta.)
  • Correct: あの時(あのとき)、彼女(かのじょ)に謝(あやま)るべきだった。 (Ano toki, kanojo ni ayamaru beki datta.) –
    I should have apologized to her at that time.

Real Conversations

Here's how ~ことだ appears in modern, natural contexts, demonstrating its role in conveying experienced advice.

Scenario 1: A senior developer to a junior developer during code review.

J

Junior

このコード、どうしても複雑(ふくざつ)になってしまって… (Kono koodo, doushitemo fukuzatsu ni natte shimatte… –
This code just ends up getting so complicated…
)
S

Senior

焦(あせ)る気持(きも)ちはわかる。でも、機能(きのう)ごとに小(ちい)さくメソッドを分(わ)けることだ。それが後(あと)々の保守性(ほしゅせい)につながるんだ。 (Aseru kimochi wa wakaru. Demo, kinou-goto ni chiisaku mesoddo o wakeru koto da. Sore ga atoato no hoshusei ni tsunagarun da. – "I get that you're in a rush. But the key is to separate the methods into small chunks for each function. That leads to future maintainability.")

*Observation:* The senior dev isn't just giving an opinion. They are stating a fundamental principle of software engineering (分けることだ). The advice is direct, authoritative, and justified by a desired outcome (maintainability).

Scenario 2: Advice between two friends about public speaking.

Speaker A: 明日(あした)のプレゼン、緊張(きんちょう)で眠(ねむ)れないよ。 (Ashita no purezen, kinchou de nemurenai yo. – "I'm so nervous about tomorrow's presentation I can't sleep.")

Speaker B: わかる。でも、完璧(かんぺき)にやろうと思(おも)わないことだよ。一番(いちばん)伝(つた)えたいメッセージを一(ひと)つだけ決(き)めて、それだけはしっかり言(い)うことだ。 (Wakaru. Demo, kanpeki ni yarou to omowanai koto da yo. Ichiban tsutaetai messeeji o hitotsu dake kimete, sore dake wa shikkari iu koto da. –

I get it. But the trick is not to try to be perfect. Decide on the single most important message you want to convey, and make sure you say that one thing clearly.
)

*Observation:* Speaker B uses ことだ twice, first negatively (思わないことだよ) and then positively (言うことだ). The friendly よ softens the delivery, but the advice is still presented as a clear, effective strategy based on experience.

Scenario 3: A quote from a designer's online blog.

いいデザインとは、何(なに)かを足(た)すことではない。むしろ、余計(よけい)なものを極限(きょくげん)まで削(そ)ぎ落(お)とすことである。 (Ii dezain to wa, nani ka o tasu koto de wa nai. Mushiro, yokei na mono o kyokugen made sogiotosu koto de aru. –

Good design is not about adding something. Rather, it is the act of stripping away superfluous elements to the absolute limit.
)

*Observation:* The formal ことである construction is used to state a philosophical principle of design. It reads as an authoritative, timeless definition, perfect for an expert sharing their philosophy in writing.

Quick FAQ

  • Q: Can I use ことだ to give advice to a friend?
  • A: Yes, but with care. It's appropriate if you have more experience in the specific area you're discussing (e.g., a hobby, a job, a life challenge). Adding よ at the end (ことだよ) makes it sound friendlier and less like a lecture. If you are peers with equal experience, a softer form like ~方がいいんじゃない？ might be more natural.
  • Q: What is the difference between ~ことだ and a direct command like ~しなさい?
  • A: ~しなさい (shinasai) is a direct command, typically used by parents or teachers to children. It says, Do this! and focuses on immediate compliance. ~ことだ is not a command but a statement of principle. It explains *the way things should be done* to achieve a good result. ~ことだ has a teaching or guiding nuance, whereas ~しなさい is purely instructional.
  • Q: Is ~ことだ ever used for things that are not advice?
  • A: Yes, occasionally it can be used to express surprise or a strong emotional reaction, often in the form ~たことだ. For example, 驚(おどろ)いたことだ (Odoroita koto da) means How surprising! or What a surprise! This usage treats the emotion itself as a notable matter or event. However, its primary function for learners at this level is for giving advice.
  • Q: How does ~ことだ relate to ~ことはない?
  • A: They are related but express opposite ideas. ~ことはない (koto wa nai) means
    there is no need to do X
    or "it's not necessary to do X." It's advice *not* to do something because it's pointless. ~ことだ (in its negative ない form) is advice *not* to do something because it's a bad idea or against the rules. Compare: 心配(しんぱい)することはない (Shinpai suru koto wa nai – "There's no need to worry
    ) vs. 無理(むり)をしないことだ (Muri o shinai koto da –
    The important thing is not to push yourself too hard").
  • Q: Can I attach ~ことだ to i-adjectives or na-adjectives?
  • A: No, ~ことだ specifically nominalizes a verb phrase. You cannot attach it directly to adjectives. To express a similar idea, you would use different phrasing. For example, instead of 優(やさ)しいことだ (yasashii koto da), you would say 人(ひと)には優(やさ)しくするべきだ (Hito ni wa yasashiku suru beki da –
    You should be kind to people
    ) or 大事(だいじ)なのは優(やさ)しさだ (Daiji na no wa yasashisa da – "What's important is kindness").

Formation Table

Verb Type Dictionary Form Result
Group 1
行く
行くことだ
Group 2
食べる
食べることだ
Group 3
する
することだ

Meanings

This pattern is used to provide strong advice or to state a conclusion about what is necessary to achieve a result.

1

Strong Advice

Giving a firm recommendation based on experience or logic.

“{成功|せいこう}したいなら、{努力|どりょく}することだ。”

“{風邪|かぜ}を{引|ひ}いたなら、{暖|あたた}かくして{寝|ね}ることだ。”

Reference Table

Reference table for 给出直接建议 (~koto da)
动词形式 功能 中文对应
辞书形 + ことだ
强力肯定建议
应该...才是/关键在于...
ない形 + ことだ
强力否定建议
关键是不可以.../不要...
辞书形 + ことですよ
稍温和的建议
（真的）应该要做...
ない形 + ことですよ
稍温和的警告
（真的）不应该做...

正式程度

正式
勉強することです。

勉強することです。 (Advice)

中性
勉強することだ。

勉強することだ。 (Advice)

非正式
勉強することだ。

勉強することだ。 (Advice)

俚语
勉強しろ。

勉強しろ。 (Advice)

~ことだ 的使用方式

~ことだ

肯定建议

  • 勉強することだ 应该学习
  • 寝ることだ 应该睡觉

否定警告

  • 食べないことだ 不该吃
  • 諦めないことだ 不该放弃

建议的强度对比

温和建议
~ほうがいい 最好...
直接忠告
~ことだ 关键在于...
强烈义务
~べきだ 必须/应该（道义上）

我可以使用 ~ことだ 吗？

1

对方是你的老板吗？

YES
停！改用 ~ほうがいい。
NO
继续
2

这是成功的秘诀吗？

YES
太棒了！用 动词 + ことだ。
NO ↓

现代生活场景

📱

社交媒体

  • • ハッシュタグを使うことだ
  • • 毎日投稿することだ
🧘

自我关爱

  • • 自分を信じることだ
  • • 無理をしないことだ
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按水平分级的例句

1

{勉強|べんきょう}することだ。

You should study.

1

{早|はや}く{寝|ね}ることだ。

You should sleep early.

1

{諦|あきら}めないことだ。

You should not give up.

1

{問題|もんだい}を{解決|かいけつ}するには、{冷静|れいせい}になることだ。

To solve the problem, you should stay calm.

容易混淆

Giving Direct Advice (~koto da) 对比 beki da

Both give advice.

常见错误

✗

Taberu koto desu

✓

Taberu koto da

Keep it consistent.
✗

Tabeta koto da

✓

Taberu koto da

Use dictionary form.
✗

Sensei, iku koto desu

✓

Sensei, itta hou ga ii desu

Too rude for superiors.
✗

Iku koto da yo ne

✓

Iku koto da

Avoid softening it too much.

句型

___ ことだ。

Real World Usage

Self-help book very common

成功するには努力することだ。

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⚠️

上司面前请收敛

绝对不要对老板或长辈使用 ~ことだ。这会让你听起来像是在居高临下地给他们上课。比如对老师说 «もっと休むことですよ。» 会显得非常失礼。
🎯

加个「ね」变温柔

在日常聊天中，加上 ことだね 或 ことだよ 会让你的建议听起来温暖亲切很多。比如教朋友玩转社媒：«毎日投稿することだね。»
💬

自带“前辈”光环

这个语法非常有“前辈（Sempai）”的感觉。日本的高年级学生或职场前辈在传授人生智慧时，最喜欢用 «~ことだ» 了。

Smart Tips

Use koto da for logic.

N/A → N/A

发音

koto-da

Intonation

Keep a flat, firm tone.

Falling

koto da↓

Finality/Authority

记住它

记忆技巧

Think of 'Koto' as 'Code'—the code to success is doing what follows.

视觉联想

Imagine a wise old owl pointing at a sign that says 'Do this!'

Rhyme

To show the way, use koto da today.

Story

A master chef tells his apprentice: 'To make good soup, taste it often. That is the secret. Taste it often (ajiwau koto da).'

Word Web

助言必要論理結論指導

挑战

Write 3 pieces of advice for a new Japanese learner using 'koto da'.

文化笔记

Rarely used by subordinates.

Nominalization of verbs.

对话开场白

“

How do I get better at Japanese?

日记主题

Write advice for your younger self.

常见错误

Incorrect

正确

Incorrect

正确

Incorrect

正确

Incorrect

正确

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Test Yourself

请填入正确的形式以给出建议。

✓ Correct! ✗ Not quite. Correct answer:
使用 ~ことだ 给出建议时，动词应使用辞书形。
哪句话是对朋友最自然的建议？

✓ Correct! ✗ Not quite. Correct answer:
否定形式的建议是 动词ない形 + ことだ。
找出句子中的错误并改正。

✓ Correct! ✗ Not quite. Correct answer:
如果你想攒钱，就不应该乱花钱，所以应该用否定形式 しないことだ。

Score: /3

练习题

1 exercises
Fill in the blank.

___ ことだ。

✓ Correct! ✗ Not quite. Correct answer: 行く
Dictionary form.

Score: /1

Practice Bank

5 exercises
将单词重新排序，组成一句正确的建议。 Sentence Reorder

を / 食べない / ことだ / 甘い / すぎ / 物

✓ Correct! ✗ Not quite. Correct answer: 甘い物を食べすぎないことだ。
使用 ~ことだ 将句子翻译成日语。 翻译

关键是要早点睡觉。

✓ Correct! ✗ Not quite. Correct answer: 早く寝ることだ。
将目标与使用 ~ことだ 的对应建议连线。 Match Pairs

目标 vs 建议

✓ Correct! ✗ Not quite. Correct answer: 運動することだ, 练习することだ, 休むことだ
选择正确的否定建议形式。 填空

嫌われたくないなら、嘘を（　　）ことだ。

✓ Correct! ✗ Not quite. Correct answer: つかない
哪个选项听起来最像“专家秘诀”？ 多项选择

在 YouTube 上成功的关键是：

✓ Correct! ✗ Not quite. Correct answer: 継続することだ。

Score: /5

常见问题 (1)

Yes, but it sounds like you are lecturing them.

Scaffolded Practice

1

1

Mastery Progress

Needs Practice

Improving

Strong

Mastered

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In Other Languages

Spanish partial

Deberías

Tone.

French partial

Tu devrais

Formality.

German partial

Du solltest

Structure.

Japanese high

beki da

Moral vs Logic.

Arabic partial

yajib an

Grammar.

Chinese partial

yinggai

Context.

Learning Path

Prerequisites

Next
日语语法：“没必要……” (Koto wa nai)

相关视频

【出口日語】「ことだ」的用法（忠告、建議） YouTube

【出口日語】「ことだ」的用法（忠告、建議）

出口日語
N2语法详解：～ことだ 给出建议的专业表达 YouTube

N2语法详解：～ことだ 给出建议的专业表达

JLPT考试频道

Related Grammar Rules

C1

极端强调句式：～極まる / ～極まりない (Kiwamaru / Kiwamarinai)

你是否曾被惹恼到'非常烦人'都不足以形容？这时`極まる` (kiwamaru)和`極まりない` (kiwamarinai)就派上用场了。它们是你形容词...
A2

表达愿望：“我想...” (～tai)

### Overview 在日语学习中，表达“想做某事”是一个非常基础且核心的语法点。当我们使用日语的 `~tai` (～たい) 形式时，它直接...
B2

无法抑制的情感：〜てならない (~te naranai)

### Overview 在日语的学习过程中，表达情感的深度和层次是衡量一个人语言能力是否达到B2水平的关键指标之一。今天我们要探讨的...
A2

在做X之前 (Mae ni)

### Overview 在日语学习中，建立清晰的时间顺序是沟通的基础。今天我们要学习的语法点`前に`（mae ni）是日语中最基础且高频的...
C1

文学比喻：像……一样、仿佛 (~gotoku / ~gotoki)

### Overview 在日语学习进阶阶段，掌握 `~ごとく` (gotoku) 和 `~ごとき` (gotoki) 是从“流利表达”跨越到“文学修辞”的关键一步...
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