Some cars have an automatic transmission. This means that most of the gears shift by themselves as the car picks up speed or slows down. There is a computer in the car which best determines when to shift gears.

However, the driver always has to shift by hand to make the car go in reverse. Reverse is powerful, like first gear. Also, if the car is going up or down a very steep hill, it has to be shifted into lower gear by hand. Some cars have an extra gear called overdrive, which helps the car use less fuel over long distances.

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