She opened her eyes with a start and was about to cry out ______ she heard her father urgently telling her to keep quiet.

1. A.
   while
2. B.
   before
3. C.
   when
4. D.
   as

She opened her eyes with a start and was about to cry out ________ she heard her father urgently telling her to keep quiet.  

   A. while                         B. before                             C. when                               D. as

 She opened her eyes with a start and was about to cry out ______ she heard her father　urgently telling her to keep quiet.

A. while        B. when        C. before       D. after

She opened her eyes with a start and was about to cry out       she heard her father urgently telling her to keep quiet .

A．while       B．when       C．before      D．after

She opened her eyes with a start and was about to cry out ________ she heard her father urgently telling her to keep quiet.