21.   When the car is stopped at a traffic signal, the gas engine shuts down, conserving fuel.

22.   When the car accelerates, the battery kicks in to give the gas engine a boost.

23.   Far from abandoning the gas engine, automakers are showcasing new technologies at the Frankfurt auto show to boost fuel economy using just plain old gasoline.

24.   Gilmore had an interest in racing from his boyhood, when he built model race cars and tiny gas engines that powered them.

25.   Honda Motor Co. on Tuesday unveiled a new Civic subcompact model equipped with a gas engine and electric motor to deliver an extremely efficient drive.

26.   Hybrids combine an electric motor with the usual gas engine to deliver more mileage and less pollution.

27.   Hybrid systems are cleaner than gas engines because they switch back and forth automatically between a gas engine and an electric motor.

28.   Hybrid vehicles switch back and forth between gas engine and electric motor, which makes for a more efficient ride and reduces emissions of the global-warming gases.

29.   It runs on electricity at lower speeds when the gas engine is less efficient and switches to gas only after it picks up speed.

30.   It runs on electricity at lower speeds when the gas engine is less efficient and automatically switches to gas only after it picks up speed.