I' m Jiang Ling from Hangzhou and I' m in Class 2. There are forty-five students in my class — twenty boys and twenty—five girls. I have got two good friends. One is Hu Ning. He is on my left. He is good at maths. The other is Tu Guo. He is on my right. IT is his favourite. After school, we usually read in the library or work on the computer. Now we are having a history lesson.

    I'm Paul from London and I'm in Class 4. There are twenty-two students in class — twelve girls and ten: boys. Tim is my good friend. He is behind me. He is tall and he is good at PE. We usually play basketball on Friday afternoon. Now it's cool. We're playing basketball in the playground.

若函数y=x²﹣3x﹣4的定义域为0，m，值域为﹣$\frac{25}{4}$，﹣4，则m的取值范围是（　　）

D

    Young people can have problems with their minds. Some students become worried because they have to study very hard; others have trouble getting on well with people like their parents or classmates.

    Li Wei, a junior 2 student from Hefei, could not understand his teacher and did badly in his lessons. He became so worried about it that he started to hurt himself with a knife.

    Another 14-year-old student, Yang Fang from Guangzhou, was afraid of exams. She got very nervous, and when she looked at the paper, she couldn't think of anything to write.

    In fact, many students have mental (心理的) problems. However, most of them don't ask for advice or help. Some think they will look stupid if they go to a doctor; others don't want to talk about their secrets.

    Liang Yuezhu, a teacher, has the following advice for young people:

    Talk to your parents or teachers often.

    Take part in group activities and play sports.

    Go to a doctor if you feel unhappy or unwell.