_________ they were here now, we would be able to celebrate their wedding anniversary.
| A．Only if | B．If only | C．Because | D．When |
He smiled politely ______ Mary apologized for her drunken friends.
| A．as | B．if | C．unless | D．though |
A number of high buildings have arisen _______ there was nothing a year ago but ruins.
| A．when | B．where |
| C．before | D．until |
（2012重庆卷）—Coach, can I continue with the training?
—Sorry, you can’t ______you haven’t recovered from the knee injury.
| A．until | B．before | C．to consider | D．unless |
（2012湖南） ____ I always felt I would pass the exam, I never thought I would get an A.
A. While B. Once C. If D. Until
____ hard you try, it is difficult to lose weight without cutting down the amount you eat.
| A．However | B．Whatever | C．Whichever | D．Whenever |