Ask your classmate if the he/she was in great britain , at the zoo, in the shop last summer (week,month),2 days ago. example: were you in great britain last year? -yes , a was. when were you there ? -last spring.

-Were you in the zoo last week?
-Yes, I were.
 
-Were you in the shop yesterday?
-No, I weren't
-When were you there?-last week