1. When I __________ (look) out the window, I __________ (see) that it __________ (snow).
  2. She __________ (find) her old diary while she __________ (clean) the attic yesterday.
  3. They __________ (dance) at the club when the DJ __________ (announce) a surprise guest.
  4. While we __________ (cook) dinner, the power __________ (go) out.
  5. I __________ (not want) to go outside because it __________ (rain) all day.
  6. The phone __________ (ring) while I __________ (take) a shower.
  7. He __________ (decide) to quit his job after he __________ (think) about it for weeks.
  8. We __________ (watch) a movie when suddenly we __________ (hear) a loud noise outside.
  9. She __________ (not realize) she __________ (lose) her keys until she __________ (get) to her car.
  10. The children __________ (sleep) when their parents __________ (come) home late.
  11. I __________ (meet) my old friend while I __________ (shop) at the mall.
  12. They __________ (not attend) the meeting because they __________ (travel) in Europe.
  13. While he __________ (read) the newspaper, he __________ (find) an interesting article about space exploration.
  14. We __________ (jog) in the park when we __________ (spot) a rare bird.
  15. The students __________ (write) the exam when the fire alarm __________ (sound).
  16. She __________ (think) about changing her major while she __________ (study) for finals.
  17. The cat __________ (sit) on the windowsill when it __________ (start) to rain.
  18. I __________ (not hear) my phone because I __________ (listen) to music with headphones.
  19. They __________ (have) breakfast when they __________ (remember) they __________ (forget) to buy milk.
  20. While she __________ (walk) her dog, she __________ (bump) into an old school friend.

Answers for Self-Checking:

  1. looked ... saw ... was snowing
  2. found ... was cleaning
  3. were dancing ... announced
  4. were cooking ... went
  5. didn't want ... was raining
  6. rang ... was taking
  7. decided ... had thought
  8. were watching ... heard
  9. didn't realize ... had lost ... got
  10. were sleeping ... came
  11. met ... was shopping
  12. didn't attend ... were traveling
  13. was reading ... found
  14. were jogging ... spotted
  15. were writing ... sounded
  16. was thinking ... was studying
  17. was sitting ... started
  18. didn't hear ... was listening
  19. were having ... remembered ... had forgotten
  20. was walking ... bumped