These achievements_______ without the contribution of Qian Xuesen, a key leader of the New China's nuclear, missile and so on．
| A．would have been unthinkable | B．would not be unthinkable |
| C．would be unthinkable | D．would not have been unthinkable |
It was dark______ we arrived at the little town .
| A．that | B．until | C．since | D．before |
—Oh, I failed again
—Don’t lose heart. One more time, ________ you will succeed.
| A．so that | B．therefore | C．however | D．and |
Mary does every single bit of housework ______her husband Bob just does the dishes at times.
| A．since | B．while | C．when | D．as |
Tom enjoyed himself so much _____ he visited his best friend in Beijing last year.
A. that B which C. when D.where
______ I accept that she is not a perfect girl, I do actually like her.
| A．While | B．Since | C．Before | D．Unless |