Shortly after the accident , two ______ police were sent to the spot to keep order .
| A．dozens of | B．dozens | C．dozen of | D．dozen |
He raised his voice to make himself _______ clearly by the audience.
| A．hearing | B．to hear | C．heard | D．hear |
There were too many people in the room and he could hardly find a chair ______.
| A．to sit | B．sit | C．to sit on | D．sitting |
Rather than ______ on a crowded bus, he always prefers ______ a bicycle.
| A．riding; to ride | B．riding; riding | C．ride; to ride | D．ride; riding |
They hurried to the station only _______ that the train had left.
| A．finding | B．to find | C．found | D．find |
The president is reported _______ that country last week.
| A．to visit | B．visiting | C．to have visited | D．visited |