12.1* Complete the sentence with the past simple or past perfect

12.1* Complete the sentence with the past simple or past perfect simple form of the verb in brackets: 1. When I (try) tried to use my laptop, I realized the battery (run) _______ down. 2. I (turn) _______ the computer off, but forgot that I (not save) _______ my work. 3. I only remembered I (not pay) _______ the bill when my Internet connection (stop) _______ working. 4. When I (receive) _______ the e-mail, I couldn't understand who (send) _______ it. 5. When I (check) _______ the instructions, I understood what I (do) _______. 6. I knew I (receive) _______ a virus when I (run) _______ the anti-virus program. 7. As soon as I (download) _______ the document, I knew I (make) _______ a mistake. 8. I could see what (go) _______ wrong as soon as I (look) _______ inside the printer. 9. I knew I (press) _______ the wrong key when nothing (happen) _______. 10. When the screen (go) _______ blank, I couldn't understand how it (happen) _______.