– The kidnapped American captain was rescued from the Somali pirates（海盗）.
-- But for the help of the US Navy, he _______ freed then.
| A．may not be | B．wouldn’t have been |
| C．wouldn’t be | D．mustn’t have been |
It rained heavily overnight and not until this morning____.
| A．did it stop | B．had it stopped | C．stopped | D．it stopped |
--Do you know what caused the accident? --- No, not yet. The matter _____.
| A．is being looked into | B．was being looked into | C．looked into | D．is looked into |
A new museum is being built in our city and it’ll be accessible to the citizens when___ next year.
| A．completing | B．is completed | C．to be completed | D．completed |
Robert failed to complete his education____ he found it hard to focus on his studies.
| A．although | B．if | C．because | D．while |
We live in a society_____ there is a great deal of debate about competition.
| A．which | B．where | C．when | D．that |