Time waits for no man. But teenagers won’t realize the value of time until it’s gone.  Don’t waste your time, __________ you will regret it.
#30899
A
so
B
and
C
but
D
or
推荐题目
Doctor Smith has made another wonderful discovery, _______ great importance. 
#30394
A
which I think is of
B
which I think it is of
C
which is I think
D
I think which is
We won’t give up _______ we should fail ten times.
#79781
A
even if
B
since
C
whether
D
until