35. They should spend more time playing sports with their friends. 

should + V1: nên làm gì 

S + spend + time + Ving: ai dành bao nhiêu thời gian để làm gì 

36. Teens become healthier by playing sports with their friends and using their phone less.

become + ADJ 

by + sth: bằng ... 

play with sb: chơi với ai 

37. Living in the city is noisier than living in the country.

S + be+ ADJ +er + than + O : ss hơn 

38. She was reading a book in her room when the mailman came in.

QKTD + when + QKĐ

hành động đang xảy ra (QKTD) có hành động khác xen vào (QKĐ) 

39. John told me that he couldn't stand the noise in the city.

S + told + O + (that) + S+ V (lùi thì)

can --> could 

`color{orange}{~MiaMB~}`