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问题 解答题

某学校需刻录一批电脑光盘，若到电脑公司刻录，每张需8元（包括空白光盘费）；若学校自己刻录，除租用刻录机需120元外，每张还需成本4元（包括空白光盘费）。问刻录这批电脑光盘，到电脑公司刻录费用省，还是自刻费用省？请说明理由。

答案

解：设需刻录x张光盘，

则到电脑公司刻录费：y1=8x（元），

自己刻录费：y2=120+4x（元），

当x＞30时，y1＞y2；

当x=30时，y1=y2；

当x＜30时，y1＜y2；

因此，这批光盘多于30张时，自刻录费用省；少于30张时，到电脑公司刻录费用省；刻录30张时，两种方式费用一样。

单项选择题

The following data sufficiency problems consist of a question and two statements, labeled (1) and (2), in which certain data are given. You have to decide whether the data given in the statements are sufficient for answering the question. Using the data given in the statements plus your knowledge of mathematics and everyday facts (such as the number of days in July or the meaning of counterclockwise), you must indicate whether.

Is the value of x3y-x2y2+xy3 equal to 0 ？（）
(1) x=0
(2) y=0

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.
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阅读理解

Sometimes teens need to have some time away from their families. They may want to move out of the family for a while. Many parents will say no to this demand. But experts say it might be a good idea to let your teens live with a friend or relative.

“It was the break I need at the time,” said Richard Lerner. He is talking about the time he spent living with his grandmother when he was 15.

“It allowed me to be a different person than I was with my parents,” Lerner said. He now heads the Institute for Children, Youth and Families at Michigan State University.

Experts say teens living away from their families can test new ways of thinking and getting along with people. They may see new solutions to problems.

This is different from running away , the experts stress. Runaways are often fleeing（逃避） serious problems.

If there is conflict（冲突） at home, having a teen live elsewhere can benefit other family members. It gives everyone space to develop better relationships.

Some teens who wants some time away from family to attend a structured summer program. Others live for a while with a relative or with the family of a friend.

Joseph Kett teaches history at the University of Virginia in Charlottesville. He says living at home until the late ten years has become the norm（标准、规范） only in recent times.

“In the 17th century, children were often sent to live in other people’s home when they were about 10 or 11,” he said.

Peter Sheras teaches education at the University of Virginia. He said parents should listen when a child wants to move out. They should try to find out why the child wants some time away. Often, parents can help the child find a safe place to stay during that time. In other cases, they can meet the child’s needs at home.

71．According to this passage, many parents think it       for their children to live away from them.

A．right        B．happy        C．unsafe       D．reasonable

72．When children seriously disagree with their parents, experts suggest that parents should      .

A．punish them            B．let them live away from their parents

C．send for a teacher        D．keep them in the house

73．In this passage “structured” means        .

A．built               B．stuck         C．organized     D．drunk

74．In history,       .

A．teens never left their families        B．teens often left their parents

C．teens never went to school     D．teens never make friends with each other

75．Nowadays living away and running away from home    .

A．never happen           B．often worry parents and teachers

C．are popular                 D．are accepted by people
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