电子课本网 第54页

第54页

信息发布者:
in the street/on the road
we can't/mustn't/shouldn't turn left
in the library/reading room
we can't/mustn't/shouldn't talk loudly there
c
a
b
a
b

be friendly to our classmates. And we must listen to our teachers carefully 
It's kind of you to help others.

talk loudly in class. It's impolite. Don't run in the classroom. 
We mustn't eat or drink in class.