Let's learn to use the problem we are facing ______ a stepping-stone to future success．

A. to                B. for       C. as                   D.  by

Let’s learn to use the problem we are facing ________ a stepping-stone to future success.

Let's learn to use the problem we are facing ______ a stepping-stone to future success．

1. A.
   to
2. B.
   for
3. C.
   as
4. D.
   by

Let's learn to use the problem we are facing ____ a stepping-stone to future success．

       A．to                 B．for                      C．as                             D．by

Let’s learn to use the problem we are facing ________ a stepping-stone to future success.