Translated examples
この本は高いです。
This book is expensive.
この本は高くないです。
This book is not expensive.
昨日は寒かったです。
It was cold yesterday.
昨日は寒くなかったです。
It was not cold yesterday.
旅行はよかったです。
The trip was good.
おいしいパンを買いました。
I bought delicious bread.
I-adjectives change their own final い to express negatives and past time. Polite です can follow the adjective, but it does not take over the normal adjective conjugation. Learn 高い, 高くない, 高かった, and 高くなかった as a connected set.
Formation and use
| Form | 高い | いい |
|---|---|---|
| ＋ | 高い | いい |
| － | 高くない | よくない |
| past ＋ | 高かった | よかった |
| past － | 高くなかった | よくなかった |
Remove the final い for the negative くない and past かった. To make the negative past, use くなかった. Keep earlier い sounds in words such as おいしい: おいしくない.
The adjective いい uses よ for these forms: よくない, よかった, よくなかった. いい天気 is a normal affirmative phrase, but いかった is not its past.
Comparisons and common errors
Polite examples are 高いです, 高かったです, 高くないです; 高くありません is another polite negative. Do not form the usual past as 高いでした.
Not every word ending in written い is an i-adjective. きれい and 嫌い are na-adjectives. Before a noun, an i-adjective attaches directly: 高い本. It does not take な.
Practise with explanations
Try the 10 questions below, or open the practice set. Check each answer or the whole set, read the explanation, and retry mistakes. First-attempt results are kept separately on this device.
Connected lessons
Sources
Try what you have just read
Recognise the pattern, write an answer from memory, then use it in a short reading. Your existing progress carries over.
Open the three-step lessonRelated Grammar
Japanese Na-Adjectives: Na, Da, and Conjugation
A na-adjective uses な before a noun but behaves much like a noun predicate at the end of a sentence. Compare 静かな部屋 with 部屋は静かです. Practise with 10 explained questions.
Put Japanese Adjectives Before Nouns
A Japanese adjective comes before the noun it describes. The connector depends on the adjective class: 新しい本 but 静かな部屋. Practise with 10 explained questions.
Kute and De: Connect Japanese Descriptions
To link descriptions, use くて for an i-adjective and で for a na-adjective or noun. The last predicate supplies the final tense and politeness. Practise with 10 explained questions.