Experiments of this kind ___in both the U.S and Europe well before the Second World War.
#102411
A
had conducted
B
have conducted
C
have been conducted
D
had been conducted
推荐题目
Fresh air, enough exercise and nutritious food ______ to sound health.
#100792
A
devote
B
add
C
contribute
D
stick
---I’ve heard you ___ here. What is it like？ ---Very hard. But as long as the pay covers the expenses for my next school term, It’s ok.
#101628
A
work
B
have worked
C
are working
D
will work
—How long have you been in this office?—Just a few minutes. My cousins__________ here together with me.
#104311
A
have walked
B
had walked
C
walked
D
have been walking
－The enemy spy was found at last. －Really? Where ________ himself?
#104754
A
had he hidden
B
did he hide
C
has he hidden
D
was he hidden
—Are you feeling better?—Sure. I _______the medicine according to the directions.
#101349
A
took
B
take
C
will take
D
have been taking