They were trying to remove harmful ___________ from cigarettes.
| A．content | B．substances | C．materials | D．mixtures |
You’d better find an English pen friend ___ improve your writing.
| A．so that | B．in order that | C．to | D．for |
There are 2100 students __ all in our school.
| A．for | B．at | C．by | D．in |
You’d better __ electricity; it would be dangerous.
| A．look out | B．take care of | C．watch out for | D．care about |
Mum, I think I’m __ to get back to school.---Not really, my dear.You’d better stay at home for another day or two.
| A．so well | B．so good | C．well enough | D．good enough |
We were all surprised when he made it clear that he ___ office soon.
| A．leaves | B．would leave | C．left | D．had left |