This is how we add something descriptive to nouns.

Verbs

To modify a noun with a verb we need to use the standard form of the verb before the noun which we want to modify.

食たべる　時間じかん。

Time to eat.

見みた　映画えいが。

Film I saw.

送おくる　手紙てがみ。

Letter to send.

飲のまなかった　コーヒー。

Coffee I did not drink.

買かわない　傘かさ。

Umbrella I will not buy.

The same logic applies to the auxiliary verb. In the above sentences the subject is assumed to be the speaker because we do not have enough information to know otherwise.

先生せんせいじゃない　人ひと。

Person who is not a teacher.

学生がくせいだった　ころ。

Time when I was a student.

学生がくせいじゃなかった　美紀子みきこ。

Mikiko who was not a student.

For the affirmative auxiliary verb we need a third form of the auxiliary verb which will be introduced later.

学生がくせいである　人ひと。

Person who is a student.

Adjectives

Similar to English, to modify a noun with an adjective in Japanese we simply place the adjective before the noun.

The car.

The expensive car.

I-Adjectives

I-adjectives are simple. All we need do is place them before the noun we want to modify.

おいしい　料理りょうり。

Delicious food.

安やすい　財布さいふ。

Cheap wallet.

We can only modify the noun with the standard form of the adjective. In Japanese, whether the sentence is standard or polite is determined by the form of the final verb.

やさしいです　先生せんせい。(✘)

やさしい　先生せんせい。(✔)

Kind teacher.

What about negative sentences? Well, we can either modify the adjective or modify the auxiliary verb which give rise to the same meaning but using slightly different logic—as is the case in English.

面白おもしろくありません　映画えいが。(✘)

面白おもしろくない　映画えいが。(✔)

Uninteresting film.

彼かれは　やさしくない　先生せんせいです。

He is an unkind teacher.

彼かれは　やさしい　先生せんせいではありません。

He is not a kind teacher.

A similar logic applies to past and past negative sentences; however, here it is almost always more natural to modify the auxiliary verb.

彼かれは　やさしかった　先生せんせいです。(△)

He is a teacher that was kind.

彼かれは　やさしい　先生せんせいでした。(OK)

He was a kind teacher.

Na-Adjectives

I-adjectives are so called because they end with い. Na-adjectives, on the other hand, do not end with な. This is a syllable we need to add to the adjective when modifying nouns.

【na-adjective】＋　な　＋【noun】

彼女かのじょは　きれいな　女性じょせいです。

She is a beautiful lady.

ここは　便利べんりな　場所ばしょです。

This is a convenient place.

これは　有名ゆうめいな　映画えいがです。

This is a famous film.

Note also that the auxiliary verb is omitted. In other words, the following is incorrect:

ここは　便利べんりだな　場所ばしょです。(✘)

This is a convenient place.

What if we want to form negative, past, or past negative tense expressions? Here we include the auxiliary verb and exclude the な syllable.

彼女かのじょは　まじめだった　学生がくせいです。

She is a student that was serious.

But, as before, modifying the auxiliary verb is far more natural in the vast majority of cases.

彼女かのじょは　まじめな　学生がくせいでした。

She was a serious student.