If we ________ now to protect the environment, we’ll live to regret it.
| A．hadn’t acted | B．haven’t acted |
| C．don’t act | D．won’t act |
As your teacher, I could not have you ______ away with cheating in the exam.
| A．get | B．getting | C．breaking | D．break |
Going abroad to study requires a big adjustment and it usually takes a while to .
| A．calm down | B．fit in | C．keep up | D．cheer up |
Failure can make a positive contribution to your life _______ you learn to use it.
| A．since | B．unless | C．until | D．once |
The police have issued a detailed ____________ of the missing boy.
| A．direction | B．expression | C．description | D．instruction |
—Did you receive my letter?
—I received one just as I .
| A．set out | B．had set out | C．was setting out | D．would set out |