In the lab, keeping things clean and organized can help provide a safer ________.
| A． |
system |
B． |
method |
C． |
investment |
D． |
environment |
They didn’t know how the change had.
| A．been taken place | B．happen |
| C．come about | D．broke out |
—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 |