The real reason why prices ____ , and still are, too high is complex, and no short discussion can satisfactorily explain this problem.
Not only ________learn a foreign language, but also ______ master it well.
| A．must we ; we must | B．must we ; must we |
| C．we must ;’ we must | D．we must ; must we |
______ with a moon rover(月球车) called “Yutu” (Jade Rabbit) , Chang'e-3 successfully landed on the moon.
| A．Being equipped | B．Having equipped | C．To be equipped | D．Equipped |
All their attempts to rescue the child from the burning building were _____, and he died soon.
| A．in place | B．in return | C．in vain | D．in ruins |
Be careful when you cross this busy street. _____, you may get run over by a car.
| A．If not | B．If so | C．If any | D．if possible |
Smoking is so harmful to people’s health that it kills __________ people each year than automobile accidents.
| A．seven more times | B．seven times more | C．over seven times | D．seven times |