____private cars are bringing us convenience,they also cause

____private cars are bringing us convenience,they also cause Are they American cars? Look!They are ______their cars. 是Are they cars还是Are these cars? there are lots of cars.old cars are a major cause of polluti They are English cars.(改为单数形式) Are they American cars?（改为单数） They are English cars改为否定句 Cars do cause us some health problems--in fact far more seri Cars do cause us some health problem —in fact more serious o Cars do cause us some health problems-in fact far more serio Where are our cars?-----They are over there.________________