Scientists say it may be five years ______ it is possible to test this medicine on human patients．
#31988
A
since
B
until
C
before
D
when
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Although the police thought he was the most likely one, _____ they had no exact proof about it, they could not arrest him.
#32949
A
when
B
until
C
before
D
since
I was so familiar with her that I recognized her voice ________ I pickedup the phone.
#31811
A
the moment
B
after
C
before
D
while
My father asked me ______ with me.
#32724
A
what the matter is
B
what the mater was
C
what is the matter
D
what was the matter