Japanese I-Adjective Adverbs (～く form)
い for く to describe actions or changes.
Grammar Rule in 30 Seconds
To turn an i-adjective into an adverb, simply drop the final 'い' and add 'く'.
- Drop the final 'い' from an i-adjective: {高い|たかい} (high) becomes {高く|たかく}.
- Add 'く' to create the adverbial form: {速い|はやい} (fast) becomes {速く|はやく} (quickly).
- Use this form to modify verbs: {速く|はやく} {走る|はしる} (run quickly).
Overview
Japanese I-adjectives (い形容詞 - i keiyōshi) are fundamental descriptive words that you've likely encountered early in your studies. They directly modify nouns (e.g., 高い たか ビル - takai biru - a tall building) or act as predicates at the end of a sentence (e.g., ビルは高い たか - biru wa takai - The building is tall). However, to describe how an action is performed, which is an adverb's role, I-adjectives undergo a specific and essential transformation.
This process involves dropping the final い (i) and appending く (ku), resulting in the adverbial form or ～く (~ku) form.
This ～く form is not merely a superficial change; it fundamentally alters the word's grammatical role. It shifts the adjective from describing static qualities of nouns to describing the dynamic manner, frequency, or degree of verbs. Mastering this form is crucial at the A2 CEFR level, as it unlocks the ability to describe actions and situations with greater precision and nuance.
Without it, your ability to express complex ideas about how things happen would be severely limited, forcing reliance on less natural or clunky sentence structures.
Linguistically, the ～く form is known as the renyōkei (連用形 - continuative form) of I-adjectives. This classification highlights its versatility, allowing it to connect not only to verbs to form adverbs but also to other grammatical elements, such as auxiliary verbs (like ～ない for negation) and certain particles. Understanding the renyōkei concept provides insight into the inherent flexibility and interconnectedness of Japanese grammar, showing how adjectives seamlessly integrate into broader sentence structures to convey dynamic expressions of action and change.
How This Grammar Works
～く form of an I-adjective functions primarily as an adverb, modifying verbs, other adverbs, or even entire clauses. Its role is analogous to the English suffix "-ly" (e.g., "quick" becomes "quickly"). When you use an I-adjective in its ～く form, you are specifying the manner, degree, or frequency in which an action is carried out.早い はや (hayai - early/fast) describes a time or speed. Transformed to 早く はや (hayaku), it describes the action of doing something early or fast.早い はや 電車 でん (hayai densha - a fast train) uses 早い はや as an adjective modifying the noun 電車 でん. In contrast, 早く はや 走る はし (hayaku hashiru - to run fast) uses 早く はや to modify the verb 走る はし, indicating how one runs. This transformation allows you to move from simply stating qualities to describing actions with rich detail.～く form also plays a critical role when combined with the verb なる (naru - to become). This construction, I-adjective (～く form) + なる, signifies a change of state. It means that something becomes or gets a certain way.寒く さむ なる (samuku naru - to become cold) describes the process of the weather changing from not cold to cold. This is an incredibly common and versatile pattern used to express various transformations, from environmental shifts to personal improvement or deterioration. For instance, 体が弱く よわ なる (karada ga yowaku naru) means "to become physically weak."～く form is part of a larger grammatical concept called the renyōkei (連用形). The renyōkei is a versatile stem form in Japanese, literally meaning "form that connects to verbs." This inherent connectivity is why the ～く form is so flexible; it doesn't just act as a standalone adverb but forms the base for various other grammatical structures, including negations and certain compound expressions. Understanding its renyōkei nature helps clarify why it behaves in these specific ways across different grammatical contexts.高くたか飛ぶと (takaku tobu):高いたか (takai- high) becomes高くたか, modifying飛ぶと (tobu- to fly) to mean "to fly high." (Pitch accent:たかくとぶ)美味しくおい食べるた (oishiku taberu):美味しいおい (oishii- delicious) becomes美味しくおい, modifying食べるた (taberu- to eat) to mean "to eat deliciously" or "to enjoy eating." (Pitch accent:おいしくたべる)暑くあつなる(atsuku naru):暑いあつ (atsui- hot) becomes暑くあつ, combining withなるto mean "to become hot." (Pitch accent:あつくなる)
Formation Pattern
～く adverbial form from an I-adjective is remarkably straightforward, applying to almost all I-adjectives with only one significant exception. The process involves a simple morphological substitution that transforms the adjective's ending.
い - i).
い (i).
い with く (ku).
優しい やさ (yasashii - gentle) describes a person or a quality. When you want to describe how someone speaks gently, 優しい やさ transforms into 優しく やさ 話す はな (yasashiku hanasu - to speak gently).
～く Form | Romaji | Meaning as Adverb | Example Phrase (Casual) | Example Phrase (Polite) |
高い たか | takai | high, expensive | 高く たか | takaku | highly, expensively | 高く たか 買う か (buy expensively) | 高く たか 買います か (buy expensively) |
広い ひろ | hiroi | wide, spacious | 広く ひろ | hiroku | widely, spaciously | 広く ひろ 使う つか (use spaciously) | 広く ひろ 使います つか (use spaciously) |
寒い さむ | samui | cold | 寒く さむ | samuku | coldly | 寒く さむ なる (become cold) | 寒く さむ なります (become cold) |
新しい あたら | atarashii | new | 新しく あたら | atarashiku | newly, afresh | 新しく あたら 作る つく (make newly) | 新しく あたら 作ります つく (make newly) |
忙しい いそが | isogashii | busy | 忙しく いそが | isogashiku | busily | 忙しく いそが 働く はたら (work busily) | 忙しく いそが 働きます はたら (work busily) |
嬉しい うれ | ureshii | happy, glad | 嬉しく うれ | ureshiku | happily, gladly | 嬉しく うれ 思う おも (think happily) | 嬉しく うれ 思います おも (think happily) |
いい {いい} / 良い よ
いい {いい} (ii - good) is the sole, yet critically important, exception to this straightforward rule. While it presents itself as a regular I-adjective, its adverbial form does not directly derive from いい {いい}. Instead, it reverts to its older, classical form, 良い よ (yoi), before applying the い to く transformation. Consequently, いい {いい} transforms into よく よ (yoku).
いい {いい} (ii - good) → よく よ (yoku - well, often, frequently)
いい {いい} gradually became the colloquial form of 良い よ. When forming its adverbial (renyōkei) form, modern Japanese retains the older よい stem. Therefore, you will never hear or use いく {いく} for "well" or "good"; よく よ is the only correct and natural adverbial transformation. This specific irregularity is one of the first you must internalize at the A2 level, as よく よ is an extremely common and versatile adverb.
よく よ 眠る ねむ (yoku nemuru) means "to sleep well." (Pitch accent: よく ねむる)
よく よ 行く い (yoku iku) means "to go often" or "to go frequently." (Pitch accent: よく いく)
日本語がよく よ 分かりません わ (Nihongo ga yoku wakarimasen) - I don't understand Japanese well.
When To Use It
～く form of I-adjectives is indispensable in several key grammatical constructions, primarily when you need to qualify an action or indicate a change in state. Understanding these contexts will enable you to use this form appropriately and naturally.- 1Modifying Verbs of Action (Adverbial Function):
～く form. It functions directly as an adverb, describing how, in what manner, or to what extent a verb's action is performed. This allows for rich descriptions beyond simply stating the action itself.- Manner:
彼らは楽しくサッカーをしました。{かれ|らは たの|しく サッカーをしました。} (Karera wa tanoshiku sakkaa o shimashita.) - They played soccer enjoyably. - Speed/Intensity:
もっと速く走ってください。{もっと はや|く はし|って ください。} (Motto hayaku hashitte kudasai.) - Please run faster. - Emotion/Condition:
彼女は悲しく歌った。{かのじょ|は かな|しく うた|った。} (Kanojo wa kanashiku utatta.) - She sang sadly.
～く is placed directly before the verb it modifies. This is its natural and most common position within a clause. Unlike some English adverbs, ～く adverbs rarely appear at the very end of a sentence.- 1Expressing Change of State with
なる{なる} (to become):
～く form precedes the verb なる {なる}, the construction indicates that the subject undergoes a transformation and becomes or gets the quality described by the adjective. This structure is essential for discussing dynamic changes over time, as a result of an action, or in response to a situation. It's used for physical changes, emotional shifts, or alterations in conditions.部屋が暖かくなりました。{へや|が あたた|かく なりました。} (Heya ga atatakaku narimashita.) - The room became warm.彼の日本語は上手くなってきた。{かれ|の にほんご|は うま|く なってきた。} (Kare no Nihongo wa umaku natte kita.) - His Japanese has gotten better (literally, became skillful/good). Here,上手いうま (skillful) is the irregular I-adjective that becomes上手くうま.秋になって、葉が赤くなった。{あき|に なって、は|が あか|く なった。} (Aki ni natte, ha ga akaku natta.) - With autumn, the leaves turned red.
- 1Negation of I-adjectives (
～くない～く):
～くない ～く, is built upon the ～く stem. Although often taught as a separate conjugation, recognizing it as ～く + ない {ない} (the negative form of ある - to exist, but in this context, acting as an auxiliary) reinforces the understanding of the adverbial form's role. This demonstrates how deeply integrated the ～く form is into the basic morphology of I-adjectives.この本は高くありません。{この ほん|は たか|く ありません。} (Kono hon wa takaku arimasen.) - That book is not expensive.今日は暑くないです。{きょう|は あつ|く ないです。} (Kyō wa atsuku nai desu.) - Today is not hot.
- 1Connecting Clauses (Renyōkei Function):
te-form for clause connection, the ～く form, being a renyōkei, inherently possesses a connective function. It can link two clauses, where the first clause (ending with the ～く form) describes a state or manner that provides context or reason for the second clause. This is more common in written Japanese or formal speech.彼女は寂しく、家に帰った。{かのじょ|は さび|しく、いえ|に かえ|った。} (Kanojo wa sabishiku, ie ni kaetta.) - She was lonely and went home. (Here,寂しくさび describes her state leading to the action of going home.)この映画は面白く、感動的だった。{この えいが|は おもしろ|く、かんどうてき|だった。} (Kono eiga wa omoshiroku, kandouteki datta.) - This movie was interesting and moving. (面白くおもしろ connects the two descriptive clauses.)
Common Mistakes
～く form. Identifying and understanding these common errors is key to accurate and natural Japanese usage.- 1Confusing I-adjectives with Na-adjectives: This is arguably the most prevalent mistake. Many learners incorrectly attempt to apply the
～くtransformation to Na-adjectives (な形容詞-na keiyōshi). Despite some Na-adjectives ending inい(e.g.,きれい{きれい} -kirei- beautiful/clean,きらい{きらい} -kirai- disliked), they behave grammatically differently from I-adjectives. For their adverbial form, Na-adjectives consistently take the particleに(ni), notく. This is a fundamental distinction you must internalize.
- Incorrect:
きれいくきれい書くか (kireiku kaku) - Correct:
きれいにきれい書くか (kirei ni kaku- to write neatly/beautifully) - Incorrect:
静かいくしずかする(shizukaiku suru) - Correct:
静かにしずかする(shizuka ni suru- to make quiet, to be quiet) - Tip: If an adjective can take
なbefore a noun (e.g.,きれいなきれい人{ひと}), it's a Na-adjective and uses～にfor its adverbial form.
いい {いい}よく よ:** The transformation of いい {いい} (good) to よく よ (well, often) is non-negotiable. Using いく {いく} in any context for this meaning is grammatically incorrect and will sound jarring to native speakers. This specific irregularity must be memorized through repetition and consistent application, as よく よ is one of the most frequently used adverbs in Japanese. Failure to use よく よ will immediately flag you as a non-native speaker.- Incorrect:
いく{いく}寝たね (iku neta) - Correct:
よくよ寝たね (yoku neta- I slept well.) - Incorrect:
このラーメンはいく{いく}ない{ない} (kono raamen wa iku nai) - Correct:
このラーメンはよくないよ (kono raamen wa yokunai- This ramen is not good.)
- 1Attaching
です{です} to the～くform: The～くform is an adverbial modifier; adverbs do not directly take the polite copulaです{です}. It modifies a verb, and it is the verb at the end of the sentence that carries the politeness marker. Placingです{です} after a～くform, like早くですはや (hayaku desu), creates an ungrammatical phrase. Politeness is determined by the final predicate of the sentence.
- Incorrect:
美味しくおいです。(oishiku desu.) - Correct:
美味しくおい食べます。た (oishiku tabemasu.- I eat deliciously.) - Correct:
今日は寒くさむないです。(Kyō wa samuku nai desu.- Today is not cold.)
- 1Misplacing
～くAdverbs: While Japanese word order offers some flexibility, adverbs typically precede the verb they modify for clarity and natural flow. Placing the～くform too far from its corresponding verb can make your sentence awkward or difficult to understand, especially in longer sentences. Aim to keep the adverb and verb in close proximity.
- Less Natural:
食べましたた美味しく。(tabemashita oishiku.) - Natural:
美味しくおい食べました。た (oishiku tabemashita.- I ate deliciously.) - Less Natural:
私は昨日、公園で速く走った。{わたし|は きのう、こうえん|で はや|く はし|った。} (Wordy, common mistake pattern from literal translation) - Natural:
私は昨日、公園を速く走った。{わたし|は きのう、こうえん|を はや|く はし|った。} (I ran fast in the park yesterday.)
- 1Overlooking the
～くform in negation: Sometimes learners fail to recognize that the negative form of I-adjectives,～くない～く, is fundamentally～く{～く} +ない{ない}. Understanding this internal structure helps reinforce the～くform's importance and makes negation less of a separate rule and more of a natural extension. If you're struggling to remember conjugations, breaking them down into their component parts can be very helpful.
楽しい たの (tanoshii)楽しく たの (tanoshiku) → 楽しく たの ない {ない} (tanoshiku nai - not fun)Common Collocations
～く form with specific verbs, creating natural and idiomatic expressions that are essential for fluent communication. Learning these as complete chunks rather than individual words can significantly enhance your fluency, comprehension, and make your Japanese sound more authentic. These collocations often carry nuanced meanings that go beyond a literal translation.早く はや する | To hurry, to speed up | Used when urging someone to be faster or to accelerate an action. (早くして！ - Hurry up!) |美味しく おい なる | To become delicious (taste improves) | Describes food or drink improving in taste, often after cooking or aging. |良くなる よ | To get better, to recover, to improve | Refers to improvement in health, condition, or a situation. (よくなる is from 良い よ). |高くなる たか | To become high/expensive | Can describe prices rising, or something reaching a greater height. |安く やす する | To make cheaper, to discount | Commonly used when bargaining or reducing a price. (安くしてください - Please make it cheaper.) |多く おお の | Many, a lot of (often adjectival) | Functions adjectivally before nouns (e.g., 多くの おお 人 {ひと} - many people). Note: 多い おお is I-adj, but this form acts like ～な adj. |詳しく くわ 説明 {せつめい} する | To explain in detail, elaborate | Essential for providing comprehensive information. |寂しく さび なる | To become lonely | Expresses the onset of feelings of loneliness. |正しく ただ 書く か | To write correctly, accurately | Emphasizes accuracy in writing or grammar. |楽しく たの 過ごす すご | To have a good time, spend time enjoyably | Used for enjoying one's time or a situation. |早く はや 起きる お | To wake up early | Refers to waking up at an early hour. |遅く おそ なる | To be late, to become late | Used for appointments or events. (遅くなっちゃった - I got late.) |テストに間に合うように、早くしてください。{テスト|に ま|に あ|うように、はや|くしてください。} (Tesuto ni ma ni au you ni, hayaku shite kudasai.) - Please hurry up so you can make it for the test.この料理は一晩置くと、もっと美味しくなるよ。{この りょうり|は ひとばん お|くと、もっと おい|しく なるよ。} (Kono ryouri wa hitoban oku to, motto oishiku naru yo.) - If you leave this dish overnight, it will become even more delicious.病気が良くなることを願っています。{びょうき|が よ|くなることを ねが|っています。} (Byōki ga yoku naru koto o negatte imasu.) - I hope your illness gets better.たくさんの詳しく説明してくれてありがとう。{たくさんの くわ|しく せつめい|してくれてありがとう。} (Takusan no kuwashiku setsumei shite kurete arigatou.) - Thank you for explaining in great detail**.彼女はいつも楽しく過ごしている。{かのじょ|は いつも たの|しく すご|している。} (Kanojo wa itsumo tanoshiku sugoshite iru.) - She is always having a good time (spending time enjoyably).
Quick FAQ
- Q: Can I use the
～くform with all adjectives?
No. The ～く form is exclusively for I-adjectives. Na-adjectives, which behave differently, form their adverbs using ～に (~ni). This distinction is a fundamental aspect of Japanese grammar you must always remember.
- Q: What is the primary difference between
～くand～にforms for adverbs?
The distinction lies in the type of adjective they originate from. The ～く form comes from I-adjectives (e.g., 高く たか from 高い たか), while the ～に form comes from Na-adjectives (e.g., きれいに きれい from きれい {きれい}). Both create adverbs, but the base adjective type dictates the transformation method. Think of it as a conjugational rule specific to the adjective class.
- Q: Why does
いい{いい} becomeよくよ instead ofいく{いく}?
いい {いい} is an irregular I-adjective. Its adverbial form derives from its older, classical root, 良い よ (yoi). Therefore, applying the い to く rule to 良い よ results in よく よ. This is a historical quirk of the Japanese language and a critical exception to memorize.
- Q: Can I use the
～くform at the end of a sentence?
Not typically as a standalone sentence ending in standard grammar. The ～く form is an adverbial modifier, meaning it requires a verb or another adverb to follow it. If you want to end a sentence, the adjective must be in its predicative form (e.g., 高いです たか - It is expensive) or its negative form (e.g., 高くないです たか - It is not expensive). However, in very casual, exclamatory, or truncated speech, you might occasionally hear a ～く form implying continuation, but this is not grammatically complete.
- Q: How do I make sentences containing the
～くform polite?
The ～く form itself does not change based on politeness. Politeness in such sentences is conveyed by the ending verb or predicate. For instance, 早く はや 走る はし (hayaku hashiru - to run fast, plain) becomes 早く はや 走ります はし (hayaku hashirimasu - to run fast, polite) or 早く はや 走ってください はし (hayaku hashitte kudasai - Please run fast, polite request). The adverb remains the same, but the sentence-ending expression determines the level of formality.
- Q: Can
～くmodify nouns?
No, the ～く form is an adverb, and adverbs primarily modify verbs, other adverbs, or clauses. To modify a noun, you use the I-adjective in its dictionary form (e.g., 高い たか 本 {ほん} - takai hon - an expensive book), not 高く たか 本 {ほん}. Adverbs never directly modify nouns.
- Q: Are there any other irregular I-adjectives like
いい{いい} concerning the～くform?
While いい {いい} / 良い よ is the most prominent and critical irregularity regarding the ～く form, it is generally the only significant one you need to be concerned with at the A2 level. Other I-adjectives follow the standard い to く transformation. Focus your memorization efforts on いい {いい} → よく よ.
I-Adjective Adverbial Conjugation
| Adjective (Dictionary) | Meaning | Adverbial Form (Ku) | Example Sentence |
|---|---|---|---|
|
{高い|たかい}
|
High/Expensive
|
{高く|たかく}
|
{高く|たかく} {売る|うる}
|
|
{速い|はやい}
|
Fast
|
{速く|はやく}
|
{速く|はやく} {走る|はしる}
|
|
{安い|やすい}
|
Cheap
|
{安く|やすく}
|
{安く|やすく} {買う|かう}
|
|
{大きい|おおきい}
|
Big
|
{大きく|おおきく}
|
{大きく|おおきく} {書く|かく}
|
|
{寒い|さむい}
|
Cold
|
{寒く|さむく}
|
{寒く|さむく} {なる|なる}
|
|
{忙しい|いそがしい}
|
Busy
|
{忙しく|いそがしく}
|
{忙しく|いそがしく} {働く|はたらく}
|
Meanings
The adverbial form allows an i-adjective to function as an adverb, modifying a verb rather than a noun.
Adverbial modification
Describes the manner in which an action is performed.
“{美味しく|おいしく}{食べました|たべました}。”
“{静かに|しずかに} (note: na-adj) -> {楽しく|たのしく}{遊ぶ|あそぶ}。”
Reference Table
| Form | Structure | Example |
|---|---|---|
|
Affirmative
|
Stem + く + Verb
|
{速く|はやく} {歩く|あるく}
|
|
Negative
|
Stem + く + ない
|
{速く|はやく} {ない}
|
|
Past
|
Stem + く + だった
|
{速く|はやく} {だった}
|
|
Polite
|
Stem + く + します
|
{暖かく|あたたかく} {します}
|
|
Question
|
Stem + く + ですか
|
{速く|はやく} {ですか}
|
|
Connective
|
Stem + く + て
|
{楽しく|たのしく}て {いい|いい}
|
Formality Spectrum
{大きく|おおきく} {してください|してください}。 (Requesting a change)
{大きく|おおきく} {して|して}。 (Requesting a change)
{大きく|おおきく} {して|して}！ (Requesting a change)
デカくして！ (Requesting a change)
Adjective to Adverb Transformation
Action
- {速く|はやく} Quickly
State
- {寒く|さむく} Coldly
Examples by Level
{速く|はやく} {走ります|はしります}。
I run fast.
{美味しく|おいしく} {食べました|たべました}。
I ate it deliciously.
{安く|やすく} {買いました|かいました}。
I bought it cheaply.
{楽しく|たのしく} {話します|はなします}。
I talk happily.
{もっと|もっと} {大きく|おおきく} {書いて|かいて} {ください|ください}。
Please write it bigger.
{昨日|きのう}は {遅く|おそく} {寝ました|ねました}。
I went to bed late yesterday.
{寒く|さむく} {なりました|なりました}。
It has become cold.
{忙しく|いそがしく} {働いて|はたらいて} {います|います}。
I am working busily.
{部屋|へや}を {暖かく|あたたかく} {して|して} {ください|ください}。
Please make the room warm.
{若く|わかく} {見える|みえる} {人|ひと}。
A person who looks young.
{静かに|しずかに} (na-adj) -> {短く|みじかく} {説明して|せつめいして} {ください|ください}。
Please explain it briefly.
{珍しく|めずらしく} {彼|かれ}が {来ました|きました}。
Rarely, he came.
{厳しく|きびしく} {指導|しどう} {する|する}。
To instruct strictly.
{激しく|はげしく} {雨|あめ}が {降って|ふって} {います|います}。
It is raining heavily.
{正しく|ただしく} {理解|りかい} {する|する}。
To understand correctly.
{惜しく|おしく} {負けました|まけました}。
We narrowly lost.
{等しく|ひとしく} {扱われる|あつかわれる} {べき|べき} {だ|だ}。
They should be treated equally.
{著しく|いちじるしく} {成長|せいちょう} {した|した}。
It grew remarkably.
{懐かしく|なつかしく} {思い出します|おもいだします}。
I remember it fondly.
{怪しく|あやしく} {光る|ひかる} {目|め}。
Eyes shining suspiciously.
{疎く|うとく} {なって|なって} {しまった|しまった}。
I have become out of touch.
{淡く|あわく} {光る|ひかる} {月|つき}。
The moon shining faintly.
{賢く|かしこく} {立ち回る|たちまわる}。
To act cleverly/shrewdly.
{脆く|もろく} {崩れ去る|くずれさる}。
To crumble away easily/fragilely.
Easily Confused
Both modify verbs.
Learners try to use 'ku' to modify nouns.
Both involve changing the end of the adjective.
Common Mistakes
たかいく
たかく
しずかいく
しずかに
たかいに
たかく
たかくする
たかくする
おもしろいく
おもしろく
さむいく
さむく
はやいな
はやく
たかくの
たかく
たかくに
たかく
たかいのく
たかく
たかくである
たかくある
たかくにす
たかくする
たかくにない
たかくない
たかくのする
たかくする
Sentence Patterns
___く 走ります。
___く してください。
___く なりました。
___く 成長しました。
Real World Usage
早く来て！
美味しく食べたよ。
厳しく指導します。
安く行きたいです。
温かくしてください。
激しく降ります。
Check the type
Don't add 'ni'
Use with 'suru'
Politeness
Smart Tips
Check if you need to modify a verb.
Use 'ku' + suru.
Drop the 'i', add 'ku'.
Remember 'ku' is for verbs, 'i' is for nouns.
Pronunciation
Vowel length
Ensure the 'u' in 'ku' is short.
Flat
たかく↑
Standard adverbial usage.
Memorize It
Mnemonic
Think of a 'Ku' (cool) person doing things quickly. If it's 'Ku', it's an adverb!
Visual Association
Imagine a giant 'い' falling off a cliff and being replaced by a 'く' shaped boomerang that flies into a verb.
Rhyme
Drop the i, add the ku, now the verb is modified by you!
Story
Taro was a very fast runner. He wanted to run faster. He took his 'i' and threw it away. He caught a 'ku' and stuck it on his shoes. Now he runs {速く|はやく}!
Word Web
Challenge
Write 5 sentences describing how you do daily tasks using the 'ku' form.
Cultural Notes
Used in all formal and informal settings.
Derived from the classical Japanese 'ku' suffix.
Conversation Starters
How do you run?
Do you like cold weather?
How should we prepare?
Is it growing fast?
Journal Prompts
Common Mistakes
Test Yourself
速___ 走る
Find and fix the mistake:
たかいに食べる
寒___ なりました。
Arrange the words in the correct order:
All words placed
Click words above to build the sentence
I ate it deliciously.
Answer starts with: 美味し...
Match each item on the left with its pair on the right:
忙しい -> ?
A: 寒いです。 B: ___してください。
Score: /8
Practice Exercises
8 exercises速___ 走る
Find and fix the mistake:
たかいに食べる
寒___ なりました。
走る / 速く / 彼は
I ate it deliciously.
速い -> ?
忙しい -> ?
A: 寒いです。 B: ___してください。
Score: /8
Practice Bank
10 exercisesもっと ___ ( {早|はや}い ) {歩|ある}いて！
{部屋|へや}を{新|あたら}しいくした。
[ {食|た}べて ] [ {美味|おい}しく ] [ ください ] [ を ] [ ご{飯|はん} ]
I woke up early.
{字|じ}を ( {綺麗|きれい} ) ___ {書|か}いてね。
{最近|さいきん}、{寒|さむ} ___ なりましたね。
Meaning match:
もっと{安|やす}くしてください。
{日本語|にほんご}を ___ {話|はな}したいです。
Score: /10
FAQ (8)
No, 'ku' forms are strictly for verbs.
They use 'ni'.
It is neutral and used everywhere.
It's the grammatical rule for conjugation.
Yes, 'ku nai'.
Extremely common.
It changes the function to adverbial.
Very few, mostly irregular adjectives.
Scaffolded Practice
1
2
3
4
Mastery Progress
Needs Practice
Improving
Strong
Mastered
In Other Languages
-mente
Japanese is agglutinative.
-ment
French is analytical.
adverbial adjective
Japanese requires conjugation.
ku-form
None.
tanwin
Different morphological system.
de
Chinese is isolating.
Learning Path
Prerequisites
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