Nothing can be done _______ he returns.
#56142
A
as
B
before
C
while
D
until
推荐题目
People cut down too many trees, _____ the greenhouse effect becomes more and more serious.
#56516
A
so
B
because
C
although
D
if
Nothing can be done _______ he returns.
People cut down too many trees, _____ the greenhouse effect becomes more and more serious.