就 or 才: sooner than expected, or later
The same slot, the opposite judgement. 就 says it happened early or easily; 才 says it happened late or only after effort — and a 才 sentence takes no final 了.
结构
时间／条件 + 就 + 动词（+ 了）→ 早、快、容易 ｜ 时间／条件 + 才 + 动词（无“了”）→ 晚、慢、费劲
讲解
本文中的中文词语都可以激活，查看词典释义。
and are both adverbs, both stand after the time phrase or subject and directly in front of the verb, and both are usually translated by nothing at all in English. What they carry is the speaker’s judgement, and the two judgements are opposites.
says the event came about earlier, faster or more easily than one might have expected: “He was here by seven” — the speaker is noting how early that is. says the opposite: “He didn’t turn up until nine.” Same arrival, same slot in the sentence, completely different comment.
The rule is the most reliable practical test at this level. A completed event with takes : . The same event with does not: . is one of the commonest errors in intermediate writing. The reason is that presents the event as barely achieved and still under discussion, which the closing contradicts.
With numbers, the same logic appears as “only so much” versus “as little as that was enough”. “He’s only eighteen” (younger than you would think); “He was working at eighteen already”.
The pair also runs through conditionals. …… promises that the condition is enough; …… insists that nothing less will do. Once you hear as “that’s all it took” and as “not before that, and not otherwise”, the connectives stop needing to be memorised.
One last habit: neither word may open the sentence. and are both wrong — an adverb never precedes the subject.
正确
Say each one out loud before moving on. The audio is a reference pronunciation, not a model to imitate exactly — match the tone contour, not the voice.
他七点就到了。他七點就到了。
Tā (first tone, high and level) qī (first tone, high and level) diǎn (third tone, dipping) jiù (fourth tone, falling) dào (fourth tone, falling) le. (neutral tone)···
He was already here at seven.
他九点才到。他九點才到。
Tā (first tone, high and level) jiǔ (third tone, dipping) diǎn (third tone, dipping) cái (second tone, rising) dào. (fourth tone, falling)···
He didn’t get here until nine.
我等了半个小时，他才来。我等了半個小時，他才來。
Wǒ (third tone, dipping) děngle (third tone, dipping) bàn (fourth tone, falling) ge (neutral tone) xiǎoshí, (third tone, dipping) tā (first tone, high and level) cái (second tone, rising) lái. (second tone, rising)···
I waited half an hour before he finally showed up.
错误 — 常见错误
These sentences are wrong. They are printed here on purpose, each one paired with the repair and the reason, because the error you can recognise is the error you stop making.
不太对
Incorrect sentence: 他九点才到了。
正确
Correct sentence: 他九点才到。
为什么: A 才 sentence takes no final 了. 才 presents the event as barely achieved, which the closing 了 undoes.
不太对
Incorrect sentence: 就他七点到了。
正确
Correct sentence: 他七点就到了。
为什么: 就 is an adverb: it follows the subject and the time word and stands immediately before the verb.
不太对
Incorrect sentence: 只要你努力，才能成功。
正确
Correct sentence: 只要你努力，就能成功。
为什么: 只要 says the condition is enough, which is the 就 judgement. 才 would deny that hard work suffices and contradict the opening clause.
对比
Most errors with this pattern are not errors about this pattern — they are a neighbouring pattern arriving at the wrong moment. Read these side by side.
The 就 of 一…就… is the same word doing the same job. 他一下课就回宿舍了 says the return followed the end of class with no delay — the “sooner than you would think” meaning, sharpened to “immediately”. That is why 才 can never appear in this frame: 他一下课才回宿舍 would claim the return was late, which contradicts 一. If you want to say the second event was slow in coming, drop 一…就… altogether: 下课以后，他半个小时才回宿舍.
As soon as: 一…就… →Learners often memorise 只要…就… and 只有…才… as arbitrary pairs. They are not: each connective simply picks the adverb whose judgement matches it. 只要 claims the condition is easy and sufficient, so it takes the “that was all it took” adverb, 就. 只有 claims the condition is hard and indispensable, so it takes the “not before that” adverb, 才. Understand the adverbs and the connectives follow — and the reverse pairings, 只要…才 and 只有…就, stop sounding possible.
Enough versus indispensable: 只要…就… and 只有…才… →小测验
第 1 题 / 3总分: 0
Choose the word that fits: the speaker thinks nine o’clock was late.
我们七点开始，他九点 ___ 到。