The heart is a（n） organ, It is of absolute importance to our body and life．
| A．vital | B．energetic | C．living | D．lively |
.I was about to get on the bus __________my wife phoned me to back home at once.
| A．when | B．while | C．until | D．after |
We must do what we can to ____________the river ______________.
| A．protect; against polluting | B．stop; polluting |
| C．keep; being polluted | D．prevent; from being polluted |
Paper produced every year is _______________the world`s production of vehicles.
| A．three times the weight | B．the three times weight |
| C．as three times heavy as | D．three times as heavier as |
—A second, please. I have another call coming through.
—_____. I’m not in a hurry.
| A．Enjoy yourself. | B．Leave me alone. | C．Why not. | D．Take your time. |
He has to finish the experiment today. He must be in the lab, ______?
| A．mustn’t he | B．won’t he | C．doesn’t he | D．isn’t he |