Pronouns

on the folowing sentances i think there is some sort of error but i dont know how to fix them. please help.

1. An American family is likely to have at least two cars in their garage.

2. The gas crisis of the early 1970s made every American driver aware of the gas mileage on their vehicles.

3. A consumer in the 1970s expected their new car to burn fuel efficiently.

4. Every automobile manufacturer in the 1990s was making their biggest profits on giant sport utility vehicles with very poor gas mileage.

5. Compared to a European or Japanese driver, an American driver today is still paying bargain prices for their gas.