Ответ:
1) 2-dropped; 3-lost; 4-happened; 5-went; 6-did; 7-was
2) 2-b; 3-a; 4-b; 5-b; 6-a; 7-b
3) 2- I bought; 3- would you invite; 4- he asked; 5- I would be; 6- somebody gave, I would have; 7- Would you be, you met; 8- would you do, you were, it stopped
4) 2- If we stayed at a hotel, it would cost too much. 3- If I told you what happened, you wouldn't believe me. 4- If she left her job, it would be hard to find another one. 5- If Kevin applied for the job, he wouldn't get it.