Experiments of this kind in both the U．S．and Europe well before the Second World War．
#102432
A
have conducted
B
have been conducted
C
had conducted
D
had been conducted
推荐题目
—I haven’t heard from Henry for a long time.—What do you suppose________ to him?
#102053
A
will happen
B
has happened
C
was happening
D
had happened
All the preparations for the task ________，and we're ready to start.
#99745
A
completed
B
complete
C
had been completed
D
have been completed
— Isn’t it hard to drive downtown to work?— Yes, that’s why I to work by train.
#103125
A
have been going
B
was going
C
have gone
D
will have gone
During the last three decades, the number of people participating in physical fitness programs___ sharply.
#100578
A
was increasing
B
has increased
C
had increased
D
will be increasing
—Don't use my handkerchief to wipe the table，gentleman.—Oh, I' m very sorry.I________clearly.
#99180
A
didn't see
B
hadn't seen
C
wasn't seeing
D
can't see