—How long do you think it will be______ man can finally solve the problem of cancer?—Well，it depends
#30976
A
when
B
until
C
after
D
before
推荐题目
The roof fell ______ the PLA men had time to rescue the child trapped in the house.
#33834
A
until
B
unless
C
before
D
because
The government has taken some measures to solve the shortage of electricity, but it may be some time _______ the situation improves.
#80093
A
since
B
when
C
unless
D
before
_______ we were studying abroad, we learned much about foreign culture and customs.
#31663
A
Since
B
While
C
After
D
During
—____when has the country been open to international trade?—1978,I suppose.
#79800
A
Since
B
In
C
From
D
After
He made a mistake, but he corrected the situation __________ it got worse.
#31740
A
until
B
when
C
before
D
as