ПОМОГИТЕ! Не могу разобраться с much\many\a lot :( переведите правильно

1. My sister works a lot .

2.They read lots of English books.

3.Does your son work a lot ?  No he is working very little now

4. He receives a lot of letters every day .

5. We read a lot and write a little in class.

6. Does your son read a lot ?  Yes he reads a lot . He usually reads in the evenings.

7. Many students know two foreign languages.

8. Don't read too much in the evening. 9. We send letters to many foreign firms.