Electronic devices such as iPods and headphones can do great harm to our hearing if _______ improperly.
#67875
A
being used
B
used
C
to be used
D
having been used
推荐题目
The          why he is absent today is          he has got a bad headache.  
#68729
A
reason; that
B
reason; because
C
cause; that
D
cause; because
If you are weak ____ a subject, ______your teacher for advice can help.
#40963
A
to, asking
B
in, ask
C
to, to ask
D
in, asking