VERB FORM: 1. People (know) how to dye even before they knew how to read and write 2. Tom was disappointed that most of the guests (leave) when he (arrive) at the party 3. I’m sure I (see) her four years ago 4. By 11 o’clock yesterday, we (arrive) at the airport 5. By 7am tomorrow, I (finish) all my work 6. Tom cleans the floor while his mother (cook) dinner. 7. They (return) to their native village after they (sell) their house in the city last month. 7. We (lose) her phone number, which makes it difficult (contact) her 8. By the time he (leave), his classmates (leave) 9. As he (drive) on a highway yesterday, he (meet) a terrible accident. 10. You can know the condition of this car only after you (use) it.