You should not go rafting ________ you know how to swim.
#31441
A
if
B
if not
C
when
D
unless
推荐题目
_____ impressed me was the boy’s ability to deal with this kind of difficult physics problem.
#30824
A
Which
B
What
C
It
D
That
We students are so busy with our homework that we have no time for outdoor exercise, ______ we have the desire.
#30111
A
wherever
B
whenever
C
even if
D
as if
—Would you tell me ____you want your tea, with sugar or milk?—Sugar, please.
#31011
A
whether
B
when
C
what
D
how
We need some more facts and figures ______ we make the final decision.
#30185
A
since
B
before
C
after
D
until