He found           very difficult           the math problem.
#52196
A
that;to solve
B
this;solving
C
it;to solve
D
it;solving
推荐题目
----________ there any food for the drivers and passengers? ----Yes, __________.
#60619
A
Are; there are
B
Is; it is
C
Are; they are
D
Is; there is
My friend Lisa is good at _____.
#54493
A
sing
B
to sing
C
singing
D
sings