____ be careful when crossing the street!
| A．Must | B．Should | C．Ought to | D．Do |
The police officers in our city work hard _____ the rest of us can live a safe life.
| A．in case | B．as if | C．in order that | D．only if |
（2011上海卷﹚If a lot of people say a film is not good, I won’t bother to see it, or I’ll wait ____ it comes out on DVD.
A. whether B. after C. though D. until
__________ volleyball is her main focus, she’s also great at basketball.
| A．Since | B．Once | C．Unless | D．While |
Bring the flowers into a warm room ___ they'll soon open.
| A．or | B．and | C．but | D．for |
Find ways to praise your children often, ____ you’ll find they will open their hearts to you.
| A．till | B．or | C．and | D．but |