1. i left. come mucho. 2. i am leaving. comió mucho. 3. he eats a lot. trabajas. 4. he ate a lot. llegaron. 5. they will arrive. llegarán. 6. they arrived. salgo. 7. you will work. trabajarás. 8. you work. salí.

1, 2, 3, 4, 6 and 8 are incorrect although I'm not sure if you're asking if they.re right or for help putting them together.

Explanation:

Just in case:

1: I left: Sali

2: I am leaving: Salgo

3: He eats a lot: Come mucho

4: He ate a lot: Comio mucho

5: They will arrive: Llegaran

6: They arrived: Llegaron

7: You will work: Trabajaras

8: You work: Trabajas

Hope this helps :)