下列词语中没有错别字的一组是( )。 A．安装 按规矩 言简意骇 瓜熟缔落，水到渠

简述中小学生心理健康的标准。

根据我国海关规定，报关企业报关注册登记证书有效期限为2年，收发货人报关注册登记证书有效期限为( )

A．2年

B．3年

C．4年

D．5年

简述演出合同的主要内容。

(二)

"Sesame Street" has been called "the longest street in the world". That is because the television program by that name can now be seen in: so many parts of the world. That program became one of American’s exports soon after it went on the air in New York in 1969.
In the United States more than six million children watch the program regularly. The viewers include more than half the nation’s preschool children, from every kind of economic, racial, and geographical group.
Although some educators object to certain elements in the program, parents praise it highly. Many teachers also consider it a great help, though some teachers find that problems arise when first graders who have learned from "Sesame Street" are in the same class with children who have not watched the program.
Tests have shown that children from all racial, geographical, and economic backgrounds have benefited from watching it. Those who watch it five times a week learn more than occasional viewers. In the US the program is shown at different hours during the week in order to increase the number of children who can watch it regularly.
The programs all use songs, stories, jokes, and pictures to give children a basic understanding of numbers, letters and human relationships. But there are some differences. For example, the Spanish program, produced in Mexico City, devotes more time to teaching whole words than to teaching separate letters.
Why has "Sesame Street" been so much more successful than other children’s shows Many reasons have been suggested. People mention the educational theories of its creators, the support by the government and private businesses, and the skillful use of a variety of TV tricks. Perhaps an equally important reason is that mothers watch it along with their children. This is partly because famous adult stars often appear on it. But the best reason for: the success of the program may be that it makes every child watching feel able to learn. The child finds himself learning, and he wants to learn more.

What is special about the program

A．It offers great fun.

B．It makes children feel able to learn.

C．It is shown at different hours during the week.

D．Children learn and enjoy themselves while watchin

设某计算机系统有一块CPU、一台输入设备、一台打印机。现有两个进程同时进入就绪状态，进程A先得到CPU运行，进程B后运行。进程A的运行轨迹为：计算50ms，打印信息100ms，再计算50ms，打印信息100ms，结束。进程B的运行轨迹为：计算50ms，输入数据80ms，再计算100ms，结束。试画出它们的时序关系图(可以用甘特图)，并说明：

进程B运行时有无等待现象若有，在什么时候发生等待现象