How many more decades will have to pass ____ scientists succeed in providing a cure for cancer?
| A．when | B．since | C．before | D．until |
You _____ read a book in the sun—it'll do harm to your eyes．
| A．couldn't | B．wouldn't | C．needn't | D．mustn't |
A fire broke out in the building at 7:30 on Tuesday morning, ____ in the death of a young girl.
| A．having resulted | B．resulted | C．being resulted | D．resulting |
—I'll call you ______ I arrive in Shenzhen．
—Thanks, and good luck．
| A．while | B．until | C．as | D．once |
Both Class 3 and our class won't be able to finish the work unless they ___ each other.
| A．team up with | B．come up with | C．put up with | D．catch up with |
Why ____ to go abroad to study when there are so many good universities at home?
| A．imagine | B．bother | C．consider | D．prevent |