--- I think the environment is becoming worse and worse.
--- Yes, I really don’t know we can do about it.

There are now many museums showing ______ life was like back then.

There is much ______ can be done about the accidents ______ from carelessness.

The clean-up operation at the bullet train crash site in east China’s Zhejiang province has been completed. Meantime, trains have resumed services on the railway ______ the accident occurred.

I wonder ____ made your English teacher so angry in her class this morning.
A   what was it that  B how was it that  C what it was that  D how it was that

It’s based on the idea _____ all people are treated equal, _____ is accepted.
A  that ; that   B which ; which    C which ; when   D that ; which

One generation plants the trees under        shade another generation rests.

I can’t understand          it is that makes him so difficult at school.

You’d better choose someone 　　you think　　　 kind and friendly to help you.

Go and get your coat. It’s 　　you left it.