Scientists say it may be five or six years ______  it is possible to test this medicine on human patients.
#92459
A
before
B
after
C
since
D
when
推荐题目
He's late, __is often the case. 
#92571
A
as
B
what
C
it
D
this
Finding her car stolen, _____.
#93600
A
a policeman was asked to help
B
the area was searched thoroughly
C
it was looked for everywhere
D
Mrs. Green reported it to the police
______ my camera wasn’t working; there is no battery in it.
#93562
A
No doubt
B
No wonder
C
No possibility
D
No way