11. (they / not / go at six)
12. (you / do everything by seven?)
13. (we / not / eat before we come, so we'll be hungry)
14. (he/ finish his exams when we go on holiday?)
15. (we arrive by the time it gets dark?)
16. (how long / you / know your boyfriend when you get married?)
17. (he/ not / complete the project by July) 18. (I/ not / finish the essay before the weekend)
19. (why/she/ finish the cleaning by six?)
20. (how long / you / be in this company when you retire?)​