I study for a test _________ working with a group.

I study for a-test by listening ________ cassettes.

1. A.
   in
2. B.
   on
3. C.
   about
4. D.
   to

I study for a test ________ working with a group．

1. A.
   in
2. B.
   by
3. C.
   at
4. D.
   to