Помогите вопрос к тексту Education in the USA (4)

Education in the United States of America is compulsory for children from the age of 6 till 16 (or 18). It involves 12 years of schooling. A school year starts at the end of August or at the beginning of September and ends in late June or early July. The whole school year is divided into three terms/trimesters or four quarters. American students have winter, spring and summer holidays which last 2 or 3 weeks and 6 or 8 weeks, respectively. The length of the school year varies among the states as well as the day length. Students go to school 5 days a week.

The American education system consists of 3 basic components: elementary, secondary and higher education. There is also such a notion as preschool education. At the age of 4 or 5 children just get acquainted with the formal education in a nursery school. The preschool education programme aims to prepare children for