The story is moving, and the questions, I suppose, are not so difficult as they appear ______.
| A．to answer | B．to be answered | C．answering | D．being answered |
You must have waited here for a long time ,___________you?
| A．mustn't | B．didn't | C．haven't | D．hadn't |
I don't remember___________ to the airport that year.
| A．to be taken | B．being taken | C．having | D．to take |
A man does not know the difficulty of anything_________ he does it personally.
| A．although | B．if | C．because | D．unless |
There is a _________ of 1000 dollars for the return
| A．reward | B．prize | C．thank | D．prsise |
Isn't it very kind __________ your parents to do that for us?
A. for B to C. about D. of