=>
6/
1. If I had a car, I could drive you to the airport.
2. If Nam weren't too young, he could take part in the project to be trained to become an astronaut.
3. If he did some exercise, he wouldn't be so unhealthy.
4. If I asked him for help, he would help me.
5. If I knew his address, I could write to him.
6. If you didn't work too fast, you wouldn't make so many mistakes.
7. If I had a map, I could direct you.
8. If English people didn't speak very quickly, I could understand them.
9. If Tom weren't fat, he could get through the bathroom window.

7/
1. studies
2. would receive 
3. is
4. have
5. will watch
6. would not be
7. will get
8. works
9. were
10. is

8/
1. you have toothache
2. I would travel around the world
3. I had a plane
4. you don't study hard
5. I would teach my students carefully
6. he hadn't had this job
7. we will wait for him
8. we will go swimming
9. we won't go swimming
10. she liked

9/
1. had/would finish
2. will stay/rains
3. see/will you ask
4. won/would give
5. will be sent/is
6. had/would buy

10/
1. needs
2. works
3. spoke
4. got
5. wanted
6. want
7. wants
8. eat
9. doesn't hurry