第二部分 阅读理解 (共20小题, 每小题2分, 满分40分)
第一节：（共15小题；每小题2分， 满分30分）
阅读下面四篇短文，从每题所给的a, b, c, d四个选项中，选出最佳选项。
a
as a student, you must be excited to know something about american school students. in fact, just like in china, in the united states, high school is usually divided into two periods; the first two or three years are called “junior high school” and the other is “senior high school”.
in china, children enjoy free education of nine years, but in the united states, the students enjoy free education(which will be started when they are about 6 years old) until they are 18 years old. as a result of the free education system (制度), american children have little difficulty in going to senior high school.
american high school students can take part in a lot of activities outside the classroom. the
