Don't fight in class. 不要在课堂上打架。

Don't climb the tree， it's too dangerous.不要爬树，它太危险。

I like climbing the tree， it's exciting.我喜欢爬树，它激动人心。

There are many tables in the classroom.教室里有许多桌子。

There is a table in my bedroom.我的卧室里有一张桌子。