The particle だけ (DAKE) is translated as "only / solely" and is placed after a quantity, a noun, or a verb to express its limit.
三人だけ生き残った。
Sannin dake ikinokotta.
Only three people survived.
2.
The particle だけ (DAKE) is used to form the structure "as... as possible" (as far as possible, etc.). だけ is then always preceded by できる (DEKIRU) (can, be able to).
できるだけ大きな声で話してください。
Dekiru dake ooki na koe de hanashite kudasai.
Please speak as loud as you can.
3.
だけ (DAKE) can be used to form the pattern “not only… but also...”
姉だけでなく兄も独身です。
Ane dake de naku ani mo dokushin desu.
Not only my sister is single, but also my brother.
4.
The particle だけ (DAKE) is used in a few phrases that express the outcome of an event.
だけ の こと は ある (DAKE NO KOTO WA ARU): the result was worth the effort
たくさんサーフィンができたので、ハワイに来ただけのことはあった。
Takusan saafin ga dekita node, hawai ni kita dake no koto wa atta.
I was able to surf a lot, so it was worth coming to Hawaii.
だけ に (DAKE NI): the result was disappointing.
2人はとても仲が良かっただけに、離婚したと聞いて驚いた。
Futari wa totemo naka ga yokatta dake ni, rikon shita to kiite odoroita.
Since they were so good together, I was surprised when I heard they got divorced.