Look! ________ fast the boy is running!

1. A.
   What
2. B.
   How
3. C.
   What a
4. D.
   What an

Look! ________ fast the boy is running!

[　　]

 –Look! The boy is running fast! –He might ______ to catch a bus.

A. run         B. running        C. is running     D. be running

—Look! The boy is running so fast!

—It’s hard to        that his right leg was once broken.

A.warn      B.find      C.imagine

–Look! The boy is running fast! –He might ______ to catch a bus.