He had to be called two or three times ________ he would come to his dinner.

A．while 

B．as

C．before 

D．until

He had to be called two or three times            he would come to his dinner.

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

He had to be called two or three times            he would come to his dinner.

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