I thought I've mastered this but I'm getting confused again.

I thought the ~く form of i-adjectives was used when the adjective modifies the noun, e.g.



I think it's named "continuative form" but I'm not sure

Am I correct?. If not, please explain me the correct use.

PS. I think the examples are correct if not please correct me.

4 Answers 4


No, the i-adjectives modify the noun in the attributive form (連体形) (which looks like the "dictionary form")

to buy a new house

When you know more Japanese, this becomes easy to remember, because both verbs and i-adjectives modify nouns this way

a person, who buys a house
"a house-buying person"

The ~く form of the i-adjective functions like an adverb, so


would mean something more like

to buy a house again/anew

Accordingly, your second example should be

I took a difficult test.

  • 2
    Actually 難しく試験した is grammatical, only the outcome is weird. It could mean something like "I did a laboratory test in a difficult way". Commented Aug 22, 2015 at 13:47
  • So 新しく modified 家を買う as a whole? Or only 買う?
    – Wreigh
    Commented Dec 17, 2019 at 0:28

The く form is used to modify verbs not nouns.

For example take the adjective 速い{はやい} which means 'to be fast'. In this form it is used to modify nouns as in 速い犬{いぬ} (a fast dog). But, when in the く form it modifies verbs as in 速く走る{はしる} (to run quickly).

When you come to study na-adjectives you'll find a similar change required. na-adjectives need な to modify a noun, but take に to modify a verb. For example take the na-adjective きれい 'to be pretty' (not an i-adjective despite ending in い). You would say きれいな犬 (a pretty dog), but きれいに書く{かく} (to write prettily).



Hayaku atarashii ie wo katta hou ga ii desu yo.

It is better to buy a new home soon.

  • 早{はや}く is an adverb to modify a verb 買{か}った, while
  • 新{あたら}しい is an adjective to modify a noun 家{いえ}.

In English, we could attach the suffix “ly” to the adjective to make it an adverb. For example, adding “ly” to the end of “beautiful”, we get “beautifully” which is an adverb. Why do we do this “trick, you may ask. The reason is that adjective can modify nouns, but it can not modify verbs. You could say “She is a beautiful girl”, but you couldn’t say “She sings beautiful”. You need to change “beautiful” to “beautifully” if you want to modify the verb “sing”. In Japanese, the way to change a I-adjective to adverb is drop the “i” and add “ku”. To change a na-adjective, you drop the “na” and add “ni”.

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