If/ people/ breath/ contaminate/ air, they/ have/ breathing problems
If people breathed contaminated air, they had breathing problems.If people breathed contaminated air, they would have breathing problems.If people breath contaminated air, they have breathing problems.If people breath contaminated air, they will have breathing problems.Hướng dẫn giải:Giải thích: câu điều kiện loại 1 “If + S V(s/es), S will V”
Dịch: Nếu mọi người hít thở không khí ô nhiễm, họ sẽ có vấn đề về hô hấp.