One way to ______ species under threat of extinction is to remove them to zoos and parks and feed them there.
| A．reserve | B．prevent | C．preserve | D．reduce |
Carl wanted to play a joke on Bob but gave himself _____ by laughing.
| A．away | B．in | C．out | D．up |
------Flight 302 to London_______ until 7:30 tomorrow morning.
-----No wonder I hear so many complaints from the passengers.
| A．has been delayed | B．delay | C．delayed | D．will be delayed |
The government is _____ and will take the necessary steps to maintain security and stability.
| A．on the alert | B．out of control | C．on guard | D．in vain |
Many people complain of the rapid _____ of modern life.
| A．rate | B．pace | C．speed | D．growth |