Иможно подробное объяснение. 1. they (to be married) for three years. 2. he (to be) at home for ten minutes. 3. he can't stand up because he (drink) too much. 4. i (often/be) to scotland. 5. i (to work) for three years in that firm. 6. the united states (to have) a new president since october. 7. he (to stop/just) smoking. 8. (to take/ever/you) a plane? 9. look at the mouse! what (to happen) to it? 10. how long (to know/they) each other? 11. i (always/to want) to become a pianist. 12. they (to live) in france for five years