For location:
* 在 (zài): This is the most common word for "in" when referring to location. It means "at," "in," or "on," and is used for both physical and abstract locations.
* Example: 我在学校。 (Wǒ zài xuéxiào.) I am at school.
For time:
* 在 (zài): It can also be used for "in" when referring to a period of time.
* Example: 我在晚上学习。 (Wǒ zài wǎnshàng xuéxí.) I study in the evening.
* 里 (lǐ): This word means "inside" or "within" and can be used for time as well.
* Example: 一小时里 (Yī xiǎoshí lǐ) In one hour.
For other contexts:
* 在 (zài): This word is versatile and can also be used for "in" in other contexts.
* Example: 在书里 (Zài shū lǐ) In the book.
* 中 (zhōng): This word means "middle" or "among" and can also be used for "in" in some cases.
* Example: 在人群中 (Zài rénqún zhōng) In the crowd.
It's important to understand the context and choose the appropriate word for "in."