Time/condition + 就 (sooner than expected) vs 才 (later than expected) + Verb
就 (jiù) vs 才 (cái) — sooner/easier than expected vs later/harder than expected
就 (jiù) and 才 (cái) both often follow a time or condition before the verb, but they signal opposite feelings about timing versus expectation. 就 signals something happens sooner, more easily, or more readily than expected — 'already, as early as, right away': 他六点就到了 (he'd already arrived by six — that's early!). 才 signals something happens later, with more effort, or only once a condition is met — 'not until, only then': 他八点才到 (he didn't arrive until eight — that's late!). The deciding question: does the timing feel surprisingly EARLY or effortless (→就), or surprisingly LATE or effortful (→才)? 就 can also mean a quick, natural consequence ('then, so'): 你一说，我就明白了 (as soon as you said it, I got it right away); 才 can mean 'only then, only if': 你解释了，我才明白 (only after you explained did I understand).
Examples
- 他六点就起床了，真早！tā liù diǎn jiù qǐ chuáng le, zhēn zǎo
He was already up by six — so early!
- 我等了半天，他十点才来。wǒ děng le bàn tiān, tā shí diǎn cái lái
I waited forever; he didn't come until ten.
- 我八点就到了，可是老师九点才来。wǒ bā diǎn jiù dào le, kě shì lǎo shī jiǔ diǎn cái lái
I had already arrived by eight, but the teacher didn't come until nine.
Common mistake
✗ Wrong: 他每天很早就起床，可是我很晚就起床。
✓ Right: 他每天很早就起床，可是我很晚才起床。
Getting up LATE is the slow/unexpected outcome, so it needs 才, not 就 — 就 would suggest getting up late was surprisingly quick or easy, which contradicts 很晚 (very late).
Practice this pattern
Fill in the missing character:
他六点＿起床了，真早！
He was already up by six — so early!