Question

Did you find ________ very interesting to play Yo-Yo?

1. A.
   this
2. B.
   it's
3. C.
   that
4. D.
   it

Answer 1

D
句意为：你发觉玩溜溜球很有趣吗？此处find的真正宾语是句尾的动词不定式，常常用it代替。