_________ difficult the task may be, we must finish it on time, because we can’t meet such a precious opportunity _______ we have expected.
| A．Whatever; that | B．However; as | C．However; that | D．Whatever；which |
The thief tried to break away from the policeman who ______ him, but failed.
| A．has held | B．had held |
| C．was holding | D．would hold |
The factory was built in a secret place, around ______ high mountains.
| A．which was | B．it was | C．which were | D．them were |
The telephone _______ three times in the last hour, and each time it ________ for my father.
| A．had rang； was | B．has rung； was |
| C．rang； has been | D．has been ringing； is |
The ______ has become extremely tense. A war could break out any time between the two sides.
| A．pollution | B．friendship |
| C．condition | D．situation |
“Aha, you’re a chain smoker！” “Only at home. Nobody _______ that but you.”
| A．discovered | B．had discovered |
| C．discovers | D．is discovering |