Question

If we planted more trees, we ... in a fresh area.

1) live 2) would live 3) will live 4) would have lived

If the people walked more, they ... healther

1) become 2) wiil become 3) would become

If people hadn`t invented machines, the environmental problems ... .

1) won`t apper 2)appeared 3)wouldn`t appear

Answer 1

 If we planted more trees, we ... in a fresh area. 2) would live - второй тип условного предложения - Если бы сажали больше деревьев, мы бы жили на чистой территории. (территории со свежим воздухом имеется ввиду)