Question

The young boy found ________ hard to finish the work alone

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

Answer 1

C
find后可加宾语从句，选A的话，宾语从句缺少主语谓语（it was）；find it +adj.作宾补，it是形式宾语，真正的宾语是动词不定式；故选C。