16.After the clock twelve, the students walked out of the lecture room.
| A．beat | B．bit | C．struck | D．rang |
---- An ant has two stomachs --- one for itself and the other for others.
----Really? Quite interesting. I ________ anything about it.
| A．don’t know | B．hadn’t known | C．haven’t known | D．didn’t know |
Scientists say it may be one year or so ________ it is possible to test the new medicine on human patients.
| A．when | B．after | C．before | D．since |
It is reported that 70% of people in China are ________ about the food security situation after so many accidents.
| A．curious | B．concerned | C．cautious | D．certain |
You have made a few mistakes in your composition but _______ you have done well.
| A．on the whole | B．first of all | C．on the other hand | D．in a word |
The big fire destroyed a 28-story high-rise apartment building , _______58 people with 56 missing and more than 120 others ______.
| A．killing, injured | B．killed, injured | C．killed, injuring | D．killing, injuring |