We are going for a picnic tomorrow. I'll call Wendy to make sure ________.

1. A.
   why to start
2. B.
   when to start
3. C.
   what to start
4. D.
   which to start

We are going for a picnic tomorrow. I’ll call Wendy to make sure ______.

A．what to start         B．why to start         C．when to start         D．which to start

We are going for a picnic tomorrow．I'll call Wendy to make sure          ．

A．why to start         B．when to start           C．what to start           D．which to start