20. The American Civil War lasted four years the North won in the end.
| A．after | B．before | C．when | D．then |
--I wonder if I could use your bike? --________.
| A．Sure. Go ahead | B．I’m sorry. Help yourself |
| C．Yes, you could | D．No, you couldn’t |
To our disappointment, some government leaders ____ their position to get illegal profit for themselves.
| A．occupy | B．take | C．abuse | D．hold |
Sarah decides to move to Hainan because she thinks that the air there is much fresher than ___ here.
| A．one | B．those | C．ones | D．that |
Although all of the apples ________, none of them ________ good.
| A．have been tasted; taste | B．have been tasted; are tasted |
| C．have tasted; taste | D．have tasted; are tasted |
With a large amount of work _______, the chief manager couldn’t spare time for a holiday.
| A．remained to be done | B．remaining to be done |
| C．remained being done | D．remaining to do |