You can take anything from the shelf and read, but please ______the books when you’ve finished with them.
| A．put on | B．put down | C．put back | D．put off |
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 |