How long have you __________ the army?
| A．joined |
| B．joined in |
| C．taken part in |
| D．been in |
If you had worked hard, you ______ so anxious now．
| A．are not | B．would not have been | C．will not be | D．would not be |
_____ I’m willing to help, I do not have much time available．
| A．While | B．When | C．Once | D．Since |
The rise of oil prices made scientists search for new energy resources ______ oil．
| A．replace | B．replacing | C．to replace | D．replaced |
You didn’t believe John won the first prize at the speech competition, ______?
| A．did he | B．didn’t he | C．did you | D．didn’t you |
I had reached a point in my career _____ I needed to decide which way to go．
| A．why | B．which | C．when | D．where |