How long do you think it will be _____ we can find a new water source?
| A．after | B．before | C．when | D．since |
Fathers often feel __________ their duty to earn more money for their family.
| A．that | B．it | C．one | D．what |
--- ________ the class done most of the work?
--- Yes, but the rest ___________ rather difficult.
| A．Has, are | B．Has, is | C．Have, are | D．Have, is |
The problem lies __________ we are now giving him a fish, not teaching him to fish.
| A．in that | B．on that | C．in which | D．on which |
We were lucky to have survived the train accident. _____, the first and last car were smashed.
| A．On top of this | B．What was worse | C．As it was | D．So it was |
Only after being attacked by the Japanese in Pearl Harbor ___in the Second World War thoroughly.
| A．had America involved | B．was America involved |
| C．America had involved | D．America was involved |