Một hành động đang xảy ra ( dùng quá khứ tiếp diễn ) thì một hành động khác xen vào ( quá khứ đơn ) , at this time yesterday: quá khứ tiếp diễn
1. wasn't driving - happened
2. broke - was doing
3. didn't go - was raining
4. were you doing - called
5. took - wasn't looking
6. were you doing
7. fell off - was painting
8. Were you watching
9. was reading - heard
10. was waiting