Here are the correctly ordered sentences:

13. We used sequence words to show the importance of our ideas.

14. Tom and his cousins used to play lots of traditional games at home.

15. I need to improve my English skills. Since I want to study abroad.

16. You can’t write in your notebook. Don’t underline the words.

For the email part, here are the best options for each blank:

(1) B. divorce
(2) A. after
(3) C. had
(4) D. uncle
(5) D. pottery