It was not until the teacher had explained it three times _______ how to work out the problem.
| A．did he understand | B．had he understood |
| C．that he understood | D．that he didn’t understood |
The teacher asked a very difficult question. It was Ted who finally _____ a good answer.
| A．came up with | B．had raised |
| C．went through with | D．put up with |
I just wonder _______ that makes him so excited.
| A．why it does | B．what it does | C．how it is | D．what it is |
-I like Tom very much_________he sometimes gives me some trouble.
-Oh, it's unbelievabae.
| A．even if | B．as if | C．even now | D．as though |
When I came back to my hometown again, I found it changed so much that I could hardly _______it。
| A．remember | B．realize | C．imagine | D．recognize |
_____people who learn Engiish as a foreign language ________more than 750 million.
| A．A number of... reach | B．The number of...come to |
| C．The number of... reaches | D．A number of...comes to |