だけ
Only, Just
Structure
［い］Adjective + だけ
［な］Adjective + な + だけ
Noun + だけ
Explanation
The particle だけ functions like 'only' or 'just' in English. It expresses the idea that out of various potential options, one specific thing is true or was selected. だけ is added directly to the dictionary form of words; however, when modifying a noun, な-adjectives must include な before だけ.
- 今日は勉強するだけ、テレビは見ない。Today I'm just going to study; I won't watch TV.
- 僕はコーヒーだけが好きだ。I only like coffee.
- このアプリは便利なだけ。This app is just convenient. (It has no other good features)
- その本は難しいだけ。That book is just difficult.
Because な-adjectives can function as nouns or as adjectives, the nuance of a sentence changes based on whether だけ follows the adjective's noun form or its adjectival form (with な).
- 田中さんは親切なだけです。Mr. Tanaka is just kind. (That's his only positive quality)
- この町は安全だけじゃない。This town isn't only safe. (It has other great qualities, too)
Essentially, this distinction emphasizes whether you are talking about a quality as an abstract concept (the noun form), or as a specific attribute of something (the adjectival form).
Examples
一杯だけです。
Only one glass.
これだけです。
Only this.
ロックだけが好き。
I only like rock music.
先生だけ知っています。
Only the teacher knows.
この本は高いだけ。
This book is just expensive.
そのホテルは静かなだけ。
That hotel is just quiet.
辛いだけだった。
It was only spicy.
子供だけ遊んでいます。
Only the children are playing.
彼だけ絵を描くのが好き。
Only he likes to draw pictures.
メールだけで連絡する。
To contact only by email.
兄は水だけ飲みます。
My older brother drinks only water.
ジムに行くのは、週末だけです。
I go to the gym only on weekends.