Сделайте, пожалуйста, в Conditional 3 эти предложения ( Те, что стоят через / , нужно объединить в одно предложение).
1) Рeople invented different machines. / Рeople built a lot of plants and factories.
2) People built a lot of plants and factories. / Plants and factories polluted the evironment.

1) If people had not invented different machines, they wouldn't have built a lot of plants and factories. 2) If people had not built a lot of plants and factories, they wouldn't have polluted the evironment.