----Who______ it be that is knocking at the door?
----It ______ be Father, but I’m not sure.
| A．can; must | B．must; can | C．can; may | D．may; must |
—The cars give off a great deal of waste gas in the street.
—Yes, But I’m sure something will be done toair pollution.
| A．reduce | B．remove | C．collect | D．warn |
When they saw they were surrounded by our troops, the enemies soldiers.
| A．gave off | B．gave up | C．gave away | D．gave in |
It’s their duty for the soldiersour countryour enemies.
| A．to prevent; from | B．to keep; from |
| C．to protect; from | D．to defend; with |
Rose was wild with joythe result of the examination.
| A．to | B．at | C．by | D．as |
There are two buildings, stands nearly a hundred feet high.
| A．the larger | B．the larger of them |
| C．the larger one that | D．the larger of which |