下课
下课 means that the class ends; in 下课后, it refers to the class finishing before the next activity. It is useful in the pattern 下课后 + an action when talking about what happens after class.
后
后 means after and follows 下课 in 下课后 to place the activity later in time. It is used after a time or event to describe what happens afterward. Use it when explaining when an activity takes place.
你
你 means you and is the person being asked about in 你做什么. It commonly comes before the verb or predicate in a question. Use it when speaking directly to one person.
做
做 means do in 你做什么, asking about the activity the other person does. It comes before 什么 in the question pattern 做什么. Use it when asking about someone’s activity.
什么
什么 means what and asks for the unknown activity after 做 in 做什么. It can follow a verb when asking what action or thing is involved. Use it when you need information about what someone does.
我
我 means I and is the subject of 我留在这里复习. It commonly comes before the action being described. Use it when talking about your own action or situation.
留
留 means stay or remain in 留在这里, showing that the speaker remains in the place. The reusable pattern is 留在 + a place. Use it when saying that you will remain somewhere instead of leaving.
在
在 marks the location of an action and comes before 这里 in 在这里. The common pattern is 在 + a place. Use it to say where an action happens or where someone remains.
这里
这里 means here and identifies the place in 留在这里 and 在这里复习. It can follow 在 to form a location phrase. Use it when referring to the place where you and the listener are.
复习
复习 means review in 我留在这里复习 and 一起在这里复习吧. It names the study activity done after class. Use it when talking about reviewing a lesson or study material.
我们
我们 means we and refers to the speaker and at least one other person in 我们可以 and 我们一起. It commonly comes before 可以 or another action. Use it when discussing an action shared by you and someone else.
可以
可以 means can or be allowed to; here it introduces the possibility of using the classroom or staying there. It comes before the action in 我们可以再用这个教室一会儿吗 and 我们可以留在这里. Use it before a verb when asking about permission or stating that an action is possible.
再
再 adds the idea of doing something for additional time in 再用这个教室一会儿. It comes before 用 and makes the request mean using the classroom a little longer. Use it before an action when asking to continue or do something additionally.
用
用 means use and takes 这个教室 as its object in 用这个教室. The common pattern is 用 + an object. Use it when talking about using a room, tool, or other resource.
这
这 means this and points to the specific classroom in 这个教室. It is used before a classifier and noun in this expression. Use it when identifying one nearby or already understood thing.
个
个 is the classifier between 这 and 教室 in 这个教室. The reusable pattern is 这 + 个 + noun for identifying one specific thing. Use it here to refer to this particular classroom.
教室
教室 means classroom and is the place being used in 这个教室. It can identify where a lesson, study activity, or other classroom activity takes place. Use it when discussing the room for a class or review session.
一会儿
一会儿 means for a short while in 再用这个教室一会儿, so the request is to use the room for a little longer. Within this expression, 一 contributes the idea of one or a, 会 refers to a short span of time, and 儿 is part of the expression’s ending. A verb can be followed by 一会儿 to describe doing it for a short time.
吗
吗 is a question particle at the end of 我们可以再用这个教室一会儿吗?. It turns the preceding statement into a yes-or-no question. Use it at the end when asking whether something is possible or allowed.
课
课 means lesson or class in 课后. In this expression, it identifies the class whose end is being discussed. It can be followed by 后 to talk about what happens after a lesson.
知道
知道 means know in 知道这个很有用, referring to knowing this information. It can be followed by information or a thing that someone knows. Use it when reacting to or stating knowledge about something.
很
很 comes before 有用 in 很有用 and helps form the description that something is useful. The common pattern is 很 + an adjective or description. Use it when describing the degree or quality of something.
有用
有用 means useful or helpful in 知道这个很有用, saying that knowing this is helpful. It follows 很 in 很有用. Use it when evaluating information, advice, or another thing as beneficial.
那
那 means then or in that case at the beginning of 那我们一起在这里复习吧. It connects the suggestion to the information or agreement just mentioned. Use it before a resulting suggestion or decision.
一起
一起 means together and shows that the review in 一起在这里复习吧 will be done jointly. It commonly comes before the action being shared. Use it when suggesting or describing an activity with another person.
吧
吧 is a suggestion particle at the end of 复习吧. It softens the statement and presents the action as a suggestion or invitation. Use it after a proposed action when inviting someone to do it.