1.Пассивный залог образуется с помощью to be и глагола в III форме(окончание ed)
1)the fire is left
2)forests are burnt
3)trees are painted
4) the water is polluted
5) litter is thrown
6)these dogs are fed
2.
1)tasty
2)who
3)safe
4)interesting
5)which
6)that