单选题 In the United States, boys and girls start school when they are five years old. In some states they must stay in school until they are sixteen. Most students are seventeen or eighteen when they graduate from high school.
Most children go to public schools. The parents don"t have to pay for their children"s education. If a child goes to a private school, his parents pay the school for the child"s education.
Today half of the high school graduates go on to colleges. A student at a state college doesn"t have to pay much if his parents live in that state. Private colleges are expensive, however. About half of the college students in the United States work while they are studying. When a student"s family is not rich, he has to earn money for part of his college expenses.

单选题 In the United States, children usually ______ when they are five.

单选题 The parents ______ if their children go to private schools.

单选题 ______ go on to colleges.

单选题 The parents pay more for their children"s education in a state college

单选题 Which of the following is true?