Being examined twice a year, whether it is a car or a bus or a truck, it is the rule that every driver____ obey in this city.
| A．shall | B．can | C．has to | D．need |
He told me the news_____, believe it or not, he had earned $1 000 in a single day.
| A．that | B．which | C．as | D．because |
The research is so designed that once _____ nothing can be done to change it.
| A．begins | B．having begun | C．beginning | D．begun |
If _____ carefully, the experiment will be successful.
| A．do | B．does | C．done | D．doing |
----- When was the People’s Liberation Army’s Navy founded?
-----It ____the April of 1949.
| A．dates to | B．dated back | C．dated from | D．dates back to |
A naval parade can provide a platform, _____ navies on behalf of different nations can communicate.
| A．in which | B．through which | C．where | D．that |