What are they talking about ________ supper?

1. A.
   when
2. B.
   in the
3. C.
   at
4. D.
   at the

—What are they talking about?

—They are talking about the photos ________ on the Great wall．

A．taking            B．were taken          C．have been taken          D．taken

__ ____are they talking about?

__Our English teacher.

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