21.   What fuels may be used in thermal power stations?

22.   American officials pointed out, however, that the losses could be considerably lower than that because it used less fuel and had lower food expenses.

23.   And the Environmental Protection Agency approved new rules drastically reducing pollution from trucks and buses using diesel fuel.

24.   Automakers whose cars and trucks use alternative fuels gain credit toward meeting federal fuel economy standards, a significant incentive.

25.   Both fuels are used for heating, and prices rise and fall with winter temperatures.

26.   Airline experts say older planes are much more expensive to operate than new models because they use more fuel and require larger cockpit staffs.

27.   But automatics use more fuel than manuals do.

28.   But they also use a fuel that the North does not produce, and they are very costly.

29.   China and Britain also are using the fuel on a test basis.

30.   Cars emit more ingredients that cause smog when they go faster because they use more fuel.