_____ suddenly occurred to me _____ I had to attend an important meeting in Shanghai the next day.
| A．It; which | B．What; that |
| C．What; which | D．It; that |
---Where did you come across our chemistry teacher ?
--- It was in the supermarket ______I purchased mooncakes．
| A．that | B．which | C．where | D．When |
________ the Internet is of great help, I don’t think it’s a good idea to spend too much time on it.
| A．While | B．As | C．Because | D．If |
—I’m really hungry now.
That’s because you have left your lunch __________.
| A．having untouched | B．to be untouched |
| C．untouched | D．being untouched |
— How much do I owe you for this supper?
— _________. It’s nothing.
| A．You are welcome | B．Forget it |
| C．With pleasure | D．That’s all right |
When Marx was in London, he _______ read at the library for hours.
| A．would | B．might | C．could | D．should |