-Have you seen Mr. Black these days, Jack?
-Yes, I met him when I ________ in the street yesterday.

1. A.
   walked
2. B.
   was walking
3. C.
   have walked
4. D.
   is walking

–Have you seen Mr. Black these days, Jack?

--Yes, I met him when I ________ in the street yesterday.

A. walked         B. was walking      C. have walked       D. is walking

----Have you seen Mr. Black these days, Jack?
----Yes, I met him when I ________ in the street yesterday.