だけ(dake) — "Only" (Neutral Limit)

• 現金だけ使えます。

  Genkin dake tsukaemasu.

  We only take cash.

  現金 (cash) + だけ (only) — limits the acceptable payment type.

• ちょっと待つだけでいい。

  Chotto matsu dake de ii.

  You just need to wait a little.

  Plain verb + だけで = "just by doing ~".

• 君だけが私の光だ。

  Kimi dake ga watashi no hikari da.

  Only you are my light.

  だけ can stack before case particles like が or を (君だけが).

• ・Nuance: だけ is emotionally neutral — it simply states a limit without judging it good or bad.
• ・Particle Math: だけ can absorb を (水だけ飲む) but stacks cleanly with に/が (僕だけに教えて = tell only me).

Commonly confused with

The JLPT rarely asks whether you recognise a pattern — it asks which of several similar patterns fits. These are the ones だけ is tested against.

• は (wa) — Topic & Contrast Particle
• が (ga) — Subject Marker & Exhaustive Listing
• を (o) — Direct Object & Traversal
• に (ni) — Target, Time, and Existence Location
• で (de) — Context of Action (Location, Means, Condition)
• と (to) — And (Exhaustive), With, and Quotation
• か (ka) — Question, Or, and Uncertain Identity
• の (no) — Possession, Modification, & Nominalization