（2012浙江卷） Had they known what was coming next, they________ second thoughts.
| A．may have | B．could have | C．must have had | D．might have had |
I have been keeping that photo ________ I can see it every day, as it always reminds me of my college days.
| A．which | B．where | C．whether | D．when |
Doing your homework is a sure way to improve your test scores, and this is especially true ________ it comes to classroom tests.
| A．as | B．since | C．when | D．after |
The roof fell ________ he had time to dash into the house to save his baby.
| A．as | B．after | C．until | D．before |
Tom make up his mind to get a seat for the football match ________ it means standing in a queue all night.
| A．as if | B．as though | C．even if | D．whatever |
________ I had walked for six hours, I was tired out.
| A．After | B．Before | C．When | D．As |