阅读下面短文，从各题所给的A、B、C、D四个选项中选出最佳答案。
As summer comes near, many children are really happy to forget about school for a few months. However, they might be taking that goal too seriously. Studies have found that children often forget between one and three months’ worth of school learning during the summer months. Spelling and math abilities drop off the most, while reading is not really influenced by the time off. The main reason for this is because most children sometimes read outside of the classroom, whether newspapers, magazines, books, or video game guides. However, their math and spelling skills only get exercised in the school setting.
The first purpose of summer holidays was to let farm children have time off to help work in the fields during the growing season, but this reason is no longer a good one since fewer kids actually work on farms today. Some cities in the United States, such as Los Angeles, have moved to a year-round school timetable, which may help reduce the loss of school skills that happens during the long summer holiday. To improve skills and to keep a good level of preparation, headmasters suggest trips to museums, summer camps, holidays with educational value, and visits to libraries to keep kids interested throughout the summer.
There are other educational systems that provide holidays while still keeping students’ skills up to date. For example, in Japan, students attend class for seven weeks in a row, followed by two weeks of holiday. This continues the whole year. In Italy, students attend class six days per week, but finish at 1: 30 pm each day, so that school does not run their life the way that it does in America, where students attend high school from 7: 45 am until 3: 00 pm each weekday. In areas where there are not enough classrooms—in Afghanistan or Somalia, for example—older students attend classes in the morning while the younger kids go to school in the afternoon.
Headmasters fear that the three-month summer holiday stops the flow of learning. Just as students become used to new math problems or new ideas in reading, writing, or thinking skills, they “shut down” during the summer holiday. When they go back to school after the long summer holiday, they take up to two months to return to their previous (先前的) level of skill. So the debate continues: whether to continue holidays or to make changes based on the Los Angeles or the Japanese models.
Which skills suffer the most over the summer holidays?

A．Math and reading.	B．Math and spelling.
C．Reading and writing.	D．Reading and thinking.

What can we learn about the first purpose of summer holidays?

A．It is still widely acceptable now.	B．It was popular in some cities.
C．It is not a good reason for city kids.	D．It was more for teachers than for students.

The underlined phrase “shut down” in the last paragraph probably means __________.

A．stop learning	B．get sick
C．go on reading	D．focus on studies

What can we infer from the passage?

A．Parents always read to their kids to keep reading skills.

B．Summer holidays lead to the loss of all the school skills.

C．Students love holidays and get their mind off learning in holidays.

D．In Italy students attend classes in the late afternoon six days a week.