Facts showed that only when they united ______ the strong enemies.
| A．could they defeat | B．they could defeat | C．they did defeat | D．had they defeat |
He always talks _______ he had been to outer space.
| A．like | B．as if /though | C．because of | D．as |
You’d better come back earlier _______ it is getting colder.
| A．as | B．and | C．but | D．or |
He was walking along the sands _______ he saw a big foot-print in the sand .
A. whileB. whenD. asD. after
_______ he was sleeping , they stole his clothes.
| A．While | B．When | C．As | D．Which |
Jack was very tired _______ he played tennis all afternoon .
| A．if | B．as soon as | C．because | D．before |