四、阅读短文，回答问题
For Chinese students in middle school, there is an important exam that everyone wants to pass. It's the Senior High School Entrance Exam (中考). It's clear that they can't enter the high school if they fail the exam. So they are really under too much pressure(压力), especially (尤其) the students in Grade 9.
They have to work harder than they did, and they usually have different school life from that in Grade 7.
One school in Suzhou surveyed 500 students in Grade 9 about how their life has changed since (自从) they were in Grade 9. There is no doubt (毫无疑问) that they spend so much time on their schoolwork that they sleep less than they did in Grade 7. Most of the students sleep less than 8 hours because they have to stay up late to finish the homework and get up at 6:00 in the morning. One good thing is that students in Grade 9 exercise more because scores of PE in the Senior High School Entrance Exam are 50 points, so the schools pay attention to the time of exercising. The survey shows the students also have no time to relax after school, such as watching TV, chatting on the phone and so on.
As for weekend activities, about 85% of the students take after-school classes, like English and Maths classes. They think it's more difficult to get better scores in these two subjects. For the PE test, they still keep exercising on weekends.
The parents are very happy to see their kids work harder for their dreams, but they all agree the kids are too tired every day.
1. What does the underlined word “they” refer to (指的是)?
Students in Grade 9.
2. Do students in Grade 9 sleep less than they did in Grade 7?
Yes, they do.
3. Why do students in Grade 9 spend more time on exercise than they did in Grade 7?
Because scores of PE in Senior High School Entrance Exam are 50 points.
4. How many students take after-school classes in the survey according to Chart 2?
425.
5. What changes happened to you after you entered Grade 8?
I spent more time on schoolwork./I had less time for outdoor sports.
解析：
【分析】
本题为阅读理解题，需结合短文内容和图表信息解答。解题思路：1. 代词指代题联系前文语境确定指代对象；2. 细节理解题直接定位原文对应内容作答；3. 图表相关题目读取数据并结合题干计算；4. 开放性题目结合自身实际合理表述。
【解析】
1. 代词指代：前文提到“especially the students in Grade 9. They have to work harder...”，可知“they”指代九年级学生。
2. 细节理解：根据短文内容“they sleep less than they did in Grade 7”，可知为肯定回答。
3. 细节理解：短文明确说明“because scores of PE in the Senior High School Entrance Exam are 50 points”，这是锻炼时间增多的原因。
4. 图表计算：Chart2显示参加课后班的比例为85%，总人数500，计算得500×85%=425。
5. 开放性问题：结合自身实际，如进入八年级后花更多时间在学业上，合理即可。
【答案】
1. Students in Grade 9.
2. Yes, they do.
3. Because scores of PE in Senior High School Entrance Exam are 50 points.
4. 425.
5. I spent more time on schoolwork./I had less time for outdoor sports.
【知识点】
阅读理解、细节理解、图表分析
【点评】
本题结合短文与图表考查学生信息提取与分析能力，题型全面，难度适中，适合中等水平学生作答。
【难度系数】
0.6
