So mysteriously ______ missing that many puzzles wait to be solved.
| A．did Flight MH370 go |
| B．Flight MH370 went |
| C．does Flight MH370 go |
| D．had Flight MH370 gone |
The young couple, who returned my lost wallet, left _______ I could ask for their names.
| A．while | B．before |
| C．after | D．since |
—I wonder how much you charge for your services.
—The first two are free the third costs $30.
| A．while | B．until |
| C．when | D．before |
It is hard for the Greek government to get over the present difficulties_________ gets more financial support from the European Union.
| A．if | B．unless |
| C．because | D．since |
------ Our holiday cost a lot of money.
------ Did it? Well, that doesn’t matter ______ you enjoyed yourselves.
| A．as long as | B．unless |
| C．as soon as | D．though |
I was so familiar with her that I recognized her voice ______ I picked up the phone.
| A．the moment | B．after |
| C．before | D．while |