I heard him______ outside.
#50192
A
sang
B
to sing
C
singing
D
sings
推荐题目
The problem is         difficult for me        work out.
#51005
A
very; to
B
enough; to
C
so; that
D
too; to
Why not _____ help when you were in trouble?
#49475
A
you ask for
B
ask for
C
asking for
D
asked for