A housing bubble is an economic situation _____ occurs when house prices rise much too fast.
#31050
A
which
B
where
C
what
D
why
推荐题目
____ a computer works is a question ___ not everyone cad answer quickly.
#34313
A
That；which
B
How；that
C
What；which
D
When；that
________ on a clear day, the beautiful scenery gives him a sense of peace.
#31219
A
Walking
B
If walking
C
While walking
D
When one is walking
The school rules state that no child shall be allowed out of the school during the day, __________ accompanied by an adult.
#32564
A
once
B
when
C
if
D
unless