Introduction
In Japanese, there are two kinds of adjectives: I-adjectives and NA-adjectives. Today, let’s learn how to use I-adjectives when they come at the end of a sentence (as predicates).
What It Means
I-adjectives describe people, things, and places.
When used at the end of a sentence, they change form to show politeness, tense (present or past), and positivity or negativity.
To make the sentence polite, we often add です after the adjective.
For negative sentences, change the ending い to く, then add ないです.
Example: おいしい → おいしくないです
When You Use It
Use an I-adjective as a predicate when you describe something at the end of a sentence.
For example:
• To say “This dish is delicious,” use the adjective with です.
• To say “This dish is not delicious,” change the い to く and add ないです.
Examples
1. Present, affirmative
このりょうりはおいしいです。
(Kono ryōri wa oishii desu.)
This dish is delicious.
2. Present, negative
このりょうりはおいしくないです。
(Kono ryōri wa oishikunai desu.)
This dish is not delicious.
3. Past, affirmative
きのうはたのしかったです。
(Kinō wa tanoshikatta desu.)
Yesterday was fun.
4. Past, negative
きのうはたのしくなかったです。
(Kinō wa tanoshikunakatta desu.)
Yesterday was not fun.
Note
The adjective いい is irregular. Its root is よ, but the non-past form is いい, not よい in everyday use.
So:
• いいです → is good
• よくないです → is not good
• よかったです → was good
• よくなかったです → was not good
Also, かっこいい (cool) is a compound adjective: かっこ (appearance) + いい.
It follows the same rules as いい:
• かっこいいです
• かっこよくないです
• かっこよかったです
• かっこよくなかったです
But be careful! かわいい (cute) is a regular I-adjective, not a compound word.
Conclusion
I-adjectives change depending on tense and whether the sentence is positive or negative.
To make your Japanese polite, remember to use です with I-adjectives in sentences.
Practice these patterns and you’ll sound more natural in your Japanese conversations!
