Do you know ________ at the bus stop?

1. A.
   whom are they waiting
2. B.
   who are they waiting for
3. C.
   whom they are waiting for
4. D.
   who they are waiting

Do you know ______ at the bus stop?

A. whom they are waiting for          B．who they are waiting 

C． whom are they waiting for        D．who are they waiting

__ ____are they talking about?

__Our English teacher.

A.What.        B.Whom            C.Whose         D.When