Some people get in touch with each other by mobile phones__________ others keep contact with each other by e-mail.
#31283
A
when
B
before
C
while
D
since
推荐题目
We know _____America is great not because it is perfect but because it can always be made better and _____ the unfinished work of perfecting the union falls to each of its citizens.
#30874
A
不填；不填
B
that ; that
C
that ; 不填
D
不填；which
He will spend six hours at his desk _______ he finishes his composition.
#79623
A
before
B
until
C
after
D
when
How can you expect to learn anything _____ you never listen?
#31297
A
in case
B
even if
C
unless
D
when
China is developing fast. That's ________ I think those of my colleagues who deal with China affairs should visit China.
#30407
A
because
B
why
C
when
D
how
Well, you can buy $20 tickets or 30 $ tickets, ______ you prefer．
#79736
A
which
B
whichever
C
whatever
D
what