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
推荐题目
Help others whenever you can ______ you will make the world a nicer place to live in.
#79975
A
and
B
or
C
unless
D
but
Take an active part in sports or other activities you enjoy ,________ you can meet various kinds of people.
#31122
A
what
B
there
C
which
D
where
A small car is big for family of three_______ you need more space for luggage.
#31282
A
once
B
because
C
if
D
unless
She missed the plane, ________driving very fast to the airport.
#31819
A
despite
B
unless
C
though
D
without
Many workers were organized to clear away_______ remained of the World Trade Center.
#79947
A
those
B
that
C
what
D
where