All flights because of the storm, they had to wait in the hall.
| A．have put off | B．were put off |
| C．have been put off | D．having been put off |
The weather was so bad that we had to ______. Our journey became a failure.
| A．turn back | B．turn away | C．turn about | D．turn round |
He hurried out and ______the chair.
| A．knocked up | B．knocked off | C．knocked back | D．knocked over |
There were signs here and there, _____ visitors to look out for ______ rocks.
| A．warning; fallen | B．warned; falling | C．to warn; fallen | D．warning; falling |
I don't doubt ______ he will pass the tomorrow’s exam.
| A．that | B．whether | C．if | D．which |
We were ______ on our way to the airport because of the heavy snow.
| A．held up | B．held out | C．held on | D．held with |