Both 才 and 就 are adverbs placed before the verb to express the speaker's SUBJECTIVE attitude about when something happened. 就 (jiù): The speaker feels the action happened EARLY, FAST, or SMOOTHLY. Often followed by 了. 才 (cái): The speaker feels the action happened LATE, SLOW, or with DIFFICULTY. NEVER followed by 了.
The same objective time can use either 才 or 就 depending on the speaker's expectation!
就 jiù — 早/快/顺利
就
说话人觉得：早了！快！顺利！ 常带"了" · often with 了
才 cái — 晚/慢/不顺利
才
说话人觉得：晚了！慢！不顺利！ 不带"了" · NEVER with 了
对比项目
就 (jiù) — 早/快/顺利
才 (cái) — 晚/慢/不顺利
说话人态度
觉得动作发生得早、快、顺利 feels it happened early/fast/smoothly
觉得动作发生得晚、慢、不顺利 feels it happened late/slow/with difficulty
常见尾缀
常带"了" often followed by 了
坚决不带"了" NEVER followed by 了
时间对照A
飞机八点起飞，他七点就到了。 He arrived at 7 — early! (plane at 8)
飞机八点起飞，他八点半才到。 He arrived at 8:30 — late! (plane at 8)
时间对照B
九点上课，他八点半就来了。 He came at 8:30 — early! (class at 9)
九点上课，他九点半才来。 He came at 9:30 — late! (class at 9)
否定形式
没就 / 不就 e.g. 他没就来（少用）
没才 / 不才 e.g. 他没才到（少用）
就 jiù — 早/快/顺利 Examples:
说话人认为动作发生得早或顺利，常带"了"。
Example: 他七点就到了。= He arrived at 7 already (speaker thinks: that's early/fast!).
才 cái — 晚/慢/不顺利 Examples:
说话人认为动作发生得晚或不顺利，后面绝对不带"了"！
Example: 他八点半才到。= He only arrived at 8:30 (speaker thinks: that's late/slow!).
Advanced 把 sentences specify WHERE something ends up (在/到) or WHO receives it (给). V在 (fàng zài): The object ends up AT a location (static result). 在 = at/in. V到 (fàng dào): The object MOVES TO a location (dynamic movement). 到 = to/into. V给 (gěi): The object is transferred TO a person. 给 = to/for (someone). CRITICAL: The preposition (在/到/给) CANNOT be omitted — it is a required part of the structure.
V在 vs V到 区别:
V在 = 强调最终位置（静态）: 把护照放在桌子上 = put the passport ON the table (it's there now)
V到 = 强调移动方向（动态）: 把护照放到包里 = put the passport INTO the bag (movement into)
⚠️ Error Alert · 常见错误：介词缺失或错位
❌
我把护照放包里了。（口语虽有，教学必须严格要求带介词）
错误！正式用法中，"放"后面必须带介词"到"或"在"，不能省略。
✅
我把护照放到包里了。
Correct! 放到 = put INTO (movement). Structure: 把 + B + 放到 + Location.
❌
他把行李箱给没给司机。
错误！否定词"没"必须放在"把"的前面，不能放在"把"的后面。
✅
他没把行李箱给司机。
Correct! 没 comes BEFORE 把. Structure: 没 + 把 + B + 给 + Person.
❌
请把行李箱放车里。（缺少介词"到"）
错误！"放"后面必须有介词"到"（移动）或"在"（位置），不能直接跟地点。
✅
请把行李箱放到车里。
Correct! 放到 = put INTO (movement to location). The preposition 到 is required.
修订例句 · Revised Examples
1美术老师把画的太阳图挂在黑板旁边，教我们怎么画落日。
měi shù lǎo shī bǎ huà de tài yáng tú guà zài hēi bǎn páng biān ， jiào wǒ men zěn me huà luò rì 。
The art teacher hung the picture of the sun next to the blackboard and taught us how to draw the sunset.