评论
打印
A.when
B.that
C.why
D.whether
2.___ has been known for about a hundred years, its commercial development has taken place since the beginning of the century.
A.WhichB.While
C.That
D.As
3.The drill has been designed so ___ through the earth to a depth of 35,000 feet.
A.to boreB.that it will bore
C.as it bore
D.boring
4.Sharon was supposed to be here at 10 o'clock. She ___ about our meeting.
A.would have forgottenB.should have forgotten
C.ought to have forgotten
D.must have forgotten
5.This may have preserved the elephant from being wiped out as well as other animals ___ in Africa.
A.huntedB.hunting
C.that hunted
D.are hunted
