In one well- know city, for example, poisonous gases from car pollute the air so much that traffic policemen have to (2) _______oxygen masksĐoạn văn8/30In one well- know city, for example, poisonous gases from car pollute the air so much that traffic policemen have to (2) _______oxygen maskstake bring wear carryGiải thíchĐáp án C