________ the heart ________ a pump, he got his friends to know the importance of it．

1. A.
   Compared; to
2. B.
   Comparing; with
3. C.
   Comparing; to
4. D.
   Compared; with

________the heart________a pump，he got his friends to know the importance of it.

A.  Compared;to           B.  Comparing;with               C.  Comparing;to         D.  Compared;with