从A、B、C、D四个选项中，选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑。
21．_____strong earthquake struck_____eastern coast of central Japan on March llth, 2011．
A．A; a B．The; the C．The; a D．A; the
22. The earthquake was so violent _________ cause a series of explosions of the nuclear reactors in several power stations.
A. to B. that C. as to D. as that
23．So far what scientists have done in forecasting the earthquake is ____ ideal．
A．next to B．far from C．out of D．due to
24.--- If we ________ the flight to Japan , we ________ in the earthquake there ..
--- Luckily you missed the flight .
A.did not miss ; would be caught B. had not missed ; would have been caught
C.don not miss ; will be caught D. should not miss ; would be caught
25．---Volunteering is becoming ____ popular in China．
