The boy was so tired that he fell asleep ______ his mother could take off his clothes．
#32555
A
before
B
after
C
while
D
when
推荐题目
___________there are many different types of food, some animals spend their lives eating only one type.
#31689
A
Since
B
Unless
C
Once
D
While
I’ll accept any job _______ I don’t have to get up early.
#33700
A
because
B
as long as
C
in case
D
though
________you never plan to visit the polar bears in the North Pole or the penguins in the South Pole，now it is the proper time to start thinking about that.
#30102
A
Until
B
Unless
C
As long as
D
Even if