35.He was sent some post cards by his friends last weeks
36.He wasn't sent some postcard by his friends last week
37.This house has been built since January
38.The Olympic games was hold every four years

35. His friends sent him some postcards last week.
36. His friends didn't send him some postcards last week.
37. They have built this house since January.
38. They hold the Olympic Games every four years.
39. Ms Huong teaches us Math at school.

35. Some postcards were sent last week
36. Some postcards weren't sent last week
37. This house has been built since  January
38. The olympic games are held every four years
39.Math is tought us at school by  ms Huong