刚 + Verb (right before the verb) vs 刚才 (standalone time word)
刚 (gāng) vs 刚才 (gāngcái) — 'just did' vs 'a moment ago'
刚 (gāng) is an adverb that sits directly in front of a verb, saying the action happened only moments ago: 我刚到 (I just arrived). 刚才 (gāngcái) is a time word meaning 'a moment ago, just now' — it behaves like other time expressions, so it can open the sentence, come before the subject, or even stand alone as an answer: 你什么时候到的？——刚才。(When did you arrive? — Just now.) The deciding question: do I need a word glued right in front of the verb, with nothing else able to come before it (→刚), or a fuller time expression that can head the sentence or stand alone (→刚才)? Because 刚 must directly precede the verb, it can never open a sentence before the subject — that position belongs to 刚才.
Examples
- 我刚到家。wǒ gāng dào jiā
I just got home.
- 刚才谁给我打电话了？gāng cái shéi gěi wǒ dǎ diàn huà le
Who called me just now?
- 刚才他还在这儿，怎么刚一转身就不见了？gāng cái tā hái zài zhèr, zěn me gāng yì zhuǎn shēn jiù bú jiàn le
He was right here a moment ago — how did he vanish the instant I turned around?
Common mistake
✗ Wrong: 刚我去了洗手间。
✓ Right: 刚才我去了洗手间。
刚 must sit directly in front of the verb (我刚去), never before the subject at the start of a sentence — for that opening position, use the standalone time word 刚才.
Practice this pattern
Fill in the missing character:
我＿到家。
I just got home.