I will thank Mary for her having offered to ________the baby while I went out.

1. A.
   have an eye for
2. B.
   keep an eye out for
3. C.
   keep an eye on
4. D.
   cast her eye over

I will thank Mary for her having offered to ________the baby while I went out.

A．have an eye for           B．keep an eye out for

C．keep an eye on               D．cast her eye over