It seemed only several minutes _______ he finished this painting .
| A．after | B．before | C．when | D．until |
Mr．Wang ______ the person referred to at the meeting be put in prison．
| A．said | B．wished |
| C．agreed | D．suggested |
It is well known to all that water, ______ enough, can change into ice quickly．
| A．if cooling | B．though to be cooled |
| C．when cooled | D．when is cooled |
I would love ______ to the party that evening, but I had an unexpected visitor．
| A．to go | B．to have gone | C．going | D．having gone |
Thomas _____ in inventing many electrical machines
| A．was successful | B．succeed | C．was success | D．successes |
The Changjiang River has been polluted badly and is not good _______．
| A．to swim it | B．to be swum in |
| C．to swim in it | D．to swim in |