—Why does the river smell terrible?
—Because large quantities of water__________．
| A．have polluted | B．is being polluted | C．has been polluted | D．have been polluted |
The blind man _____ the elephant’s trunk. It ______ like a snake.
| A．felt ; was feeling | B．felt ; felt |
| C．was feeling; felt | D．was feeling; was feeling |
—Why don't you go to medical college and be a doctor?
—Oh.It calls for a great deal of________with long training, which I am afraid I don't have.
| A．strength | B．energy | C．wisdom | D．patience |
I can't understand why he ________ so selfish. He isn't usually like that.
| A．was | B．had been | C．is | D．is being |
Jack decided to risk looking for a place to stay where he arrived, rather than booking ______.
| A．in advance | B．in return | C．in fact | D．in addition |
______ good knowledge of several languages is essential to _____ study of comparative literature because without it one can read books only in translation.
| A．A; the | B．A; / | C．The; the | D．/; the |