20. The American Civil War lasted four years the North won in the end.
| A．after | B．before | C．when | D．then |
. Garter Druse _____ his being selected for the important task to his courage，devotion and knowledge of the area.
| A．led | B．owed | C．devoted | D．thanked |
______ it have been the failure to pick up directions from the ground control that caused the air crash?
| A．Must | B．Could | C．Would | D．Should |
____ no cash for food, he broke into an old woman's house, hoping to steal some money.
| A．Because | B．As | C．Since | D．With |
--- I’m not good at dancing, you know.
--- . It’s just for fun.
| A．All right | B．No problem | C．Come on | D．Cheer up |
---I bought three DVD copies of the film Avatar and now is left. Somebody just borrows something and never returns.
---Things like that happen all the time.
| A．none | B．nothing | C．no one | D．neither |