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
I was in trouble,he would come to help me out.
#31487
A
Next time
B
The first time
C
All the time
D
Every time
39.When you read the book, you’d better made a mark ____ you have any questions.
#80395
A
at which
B
at where
C
place
D
where
I had been looking for the book for two days _______ I found it at last.
#30963
A
until
B
when
C
while
D
before
___ I saw her, she was working in a shop.
#30196
A
The last time
B
For the last time.
C
To the last time.
D
In the last time.