Reading books is very important for developing the students’ understanding of the world, ____?

Such a hard problem ________ that I ________ gave it up .

It was not until the 18th century that man realized that the whole of the brain was involved in the working of the mind，　　　　？

He hardly reads English out aloud at home, ________?

—Nothing wrong with it, ______?
—No. Yours is a specially-built model. Drive carefully, though.

You had one of your teeth pulled out yesterday, ______?

I don’t think she will come to the meeting on time,      ?

If you talk nice and polite, people listen to you. If you shout, this is no good,   ?

-----Li Ping told me that he overslept this morning.
-----Oh, he rarely used to oversleep, ________?

She must be in the classroom,           ?