How 就 and 才 Are Used With Respect to Time

In Q2 we covered using 就 to create emphasis. But y‘all are crazy smart and already locked down 就 with different meanings in different contexts. Today, we are going to teach you one more usage of 就 and introduce you to a new super sexy word, 才.  In this class, we will learn how to use 就 and 才 to express time.

First, let's try to internalize that 就 and 才 typically have opposite effects on the tone of the sentence, with 才 implying a sense of lateness, and 就 imparting a sense of earliness.

才 indicates that the speaker feels that the events discussed happened LATER than expected. Sometimes it also expresses anxiety, impatience, anger, or other related emotions. 才 can often be translated as either "until".	就 indicates that something has occurred EARLIER than the speaker expected. There may be an accompanying feeling of surprise or amazement. In this structure，了 is always proceeded by 就.
Subj.+ Time Phrase + 才+ verb	Subj. + Time Phrase + 就 + Verb +Obj+了.
Wǒ de tóngshì xiàwǔ 4 diǎn cái gěi wǒ tā de bàogào. 我的同事下午4点才给我他的报告。 My colleague didn’t give me his report until 4pm. （I am complaining my colleague gave me his report very late.）	Wǒ shàngwǔ 8 diǎn jiù gěi tā wǒ de bàogào le. 我上午8点就给他我的报告了。 I gave him my report at 8am. (I gave him very early.）
Nǐ zěnme zhème wǎn cái dào gōngsī? 你怎么这么晚才到公司？ How come you came to the company this late?! （I am complaining you come to the company very late.）	Tā zěnme nàme zǎo jiù dào gōngsī le? 他怎么那么早就到公司了？ How come he came to the company that early?! （I am surprised he came to the company very early.）
Tā bàba 50 suì cái kāishǐ xué zhōngwén. 他爸爸50岁才开始学中文。 His dad didn't start learning Chinese until he was 50. （His dad learned Chinese very late）	Tā 5 suì jiù kāishǐ xué zhōngwén le. 他5岁就开始学中文了。 His has started learning Chinese when he was 5. （He learned Chinese very early）
Tā zhège yuè cái zhǎodào gōngzuò. 他这个月才找到工作。 He didn't find a job until this month. （He found a job very late）	Tā 3 gè yuè yǐqián jiù zhǎodào gōngzuò le. 他3个月以前就找到工作了。 He found a job 3 months ago. （He found a job very early）

Note: From the sentences given, you might find Time Phrase could be 4pm, 50 years old, 3 months ago.