His report was so exciting that it was __ interrupted by applause（掌声）.
| A．constantly | B．constant | C．seldom | D．never |
________that he made an obvious mistake，Jeff went on with his speech.
| A．Not realized | B．Not realizing |
| C．Not to realize | D．Not to have realized |
There is no doubt ________ those who work hard will succeed sooner or later.
| A．if | B．whether | C．why | D．that |
There are many websites，________you can find almost all the necessary information.
| A．where | B．from where | C．when | D．from when |
If we _______ adequate preparations, the conference wouldn’t have been so successful.
| A．haven’t made | B．wouldn’t make | C．didn’t make | D．hadn’t made |
I can hardly imagine Peter ________ across the Atlantic Ocean in five days.
| A．sail | B．to sail | C．sailing | D．to have sailed |