Electric cars are powered solely by batteries.
The new hybrid vehicles switch between electricity and gasoline.
Government and private agencies have spent billions of dollars advertising the dangers of smoking.
The number of smokers is still increasing.
Some students go to a vocational school to learn a trade.
(b) Some students go to college to earn a degree
((a) The grading system at our college should be abolished. (b) The students do not like getting grades. (c) The instructors do not enjoy giving grades.