Сделайте, , 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.