I must find out why＿＿＿＿so many students made the same mistake.
| A．is it that | B．was it which | C．it is what | D．it was that |
________hard you try，it is difficult to lose weight without cutting down the amount you eat. (2012·湖南，32)
| A．However | B．Whatever |
| C．Whichever | D．Whenever |
Everything was placed exactly________he wanted it for the graduation ceremony.
(2012·天津，14)
| A．while | B．when |
| C．where | D．though |
He smiled politely ________ Mary apologized for her drunken friends. (2012·山东，27)
| A．as | B．if |
| C．unless | D．though |
I don’t believe we’ve met before，________I must say you do look familiar.
(2012·新课标全国，25)
| A．therefore | B．although |
| C．since | D．unless |
It’s not easy to change habits，________ with awareness and selfcontrol，it is possible. (2013·重庆，23)
| A．for | B．or |
| C．but | D．so |