You can’t complain of being lonely you don’t make any effort to communicate
with others.
| A．when | B．until | C．unless | D．once |
I visited Mr. Johnson during his stay in Shanghai he attended a most important conference there.
| A．when | B．which | C．where | D．in which |
The time is drawing near food raised in space will directly benefit human below.
| A．where | B．when | C．whether | D．why |
Electrical products no longer in use contain dangerous materials which can be released into the environment when they are _____.
| A．taken apart | B．given away | C．fixed up | D．handed over |
There can be little doubt _____ bombing Libya would drive thousands more to take up arms.
| A．why | B．Whether | C．that | D．How |
The train was crowded and I had to get into a carriage _______ there were already seven other passengers.
| A．which | B．where | C．what | D．when |