There is no doubt the earth is becoming warmer.
| A．whether | B．that | C．if | D．why |
You _____ such a serious mistake if you had followed his advice.
| A．may not make | B．might not make |
| C．shouldn’t have made | D．might not have made |
If only I _____ my watch!
| A．hadn’t lost | B．haven’t lost | C．didn’t lost | D．don’t lose |
What should we do if it _____ tomorrow?
| A．should snow | B．would snow | C．snow | D．will snow |
--- “What will you do during the summer holiday?”
--- “I don’t know, but it’s high time _____ something.”
| A．I’m deciding | B．I’ll decide | C．I decided | D．I decide |
I’m glad I went over all my notes; otherwise _____ .
| A．I may have failed | B．I’d fail |
| C．I’d have failed | D．I’ll have failed |