Употребите необходимую форму passive voice. 1)what bottles/ to make of? 2)when/ the telephone/ invent? 3) chees/ to make/ from milk/ 4) these houses/ build/ in 1987

1) What are bottles made of?
2) When was the telephone  invented?
3) Chees is made  from milk.
4) These houses were built in 1987.