Perhaps the day will come ____ people will be able to breathe clean air in cities．
#32785
A
when
B
while
C
as
D
since
推荐题目
(2010·福建)The girl had hardly rung the bell ________ the door was opened suddenly，and her friend rushed out to greet her.
#30449
A
before
B
until
C
as
D
since
After _____ seemed an hour or so, we were able to enter the pavilion.
#33853
A
it
B
when
C
which
D
what
Mr. Chen, ____ his lady, has a good command of the English language.
#80386
A
as well as
B
and
C
but
D
as well