1. I __________ (to read) a book when she called.
  2. She __________ (to sleep) when the earthquake happened.
  3. We __________ (to watch) TV at this time yesterday.
  4. He __________ (to work) in the garden at 8 o'clock last night.
  5. The children __________ (to play) outside when it started to rain.
  6. My friends __________ (to wait) for me when I arrived at the station.
  7. The teacher __________ (to explain) the lesson while the students were taking notes.
  8. It __________ (to snow) at this time yesterday.
  9. She __________ (to cook) dinner when I got home.
  10. They __________ (to discuss) the project when the boss walked in.
  11. I __________ (to try) to call you when you came home.
  12. The cat __________ (to sit) on the windowsill, while the birds were singing.
  13. The sun set while we __________(to walk) on the beach.
  14. My brother __________ (to play) video games when the power went out.
  15. We __________ (to have) a meeting when the fire alarm sounded.
  16. The students __________ (to not listen) to the teacher; they were talking among themselves.
  17. You __________ (to jog) in the park when I saw you yesterday.
  18. They __________ (to build) the new bridge when the accident occurred.
  19. She __________ (to take) a bath when the phone rang.
  20. The musicians __________ (to tune) their instruments when I go in.