“巴东三峡巫峡长，猿鸣三声泪沾裳”。这是下面哪部著作对三峡的描写（） A．《水经

回收塔停止进料后，应立即停止大循环系统热运。（）

臁疮的好发部位是

A．前臂下1/3

B．小腿下1/3

C．臀部下1/3

D．足部

E．以上都不是

环境标准，是指国家根据人体健康生态平衡，社会经济发展对环境结构、状态的要求，在综合考虑本国自然环境特征、科技水平和经济条件的基础上，对环境要素间的配比、布局和各环境要素的组成以及进行环保工作的某些技术要求加以限定的规范。下列规定中不属于环境标准的是（）。

A.国家关于严禁使用大排量轿车的规定

B.国家关于评定卫生城市的标准细则

C.有关部门为整治文化市场，创造良好育人环境，严扫“黄、赌、毒”的规定

D.工业局对冶金机械厂区设备烟尘排放量作检测后，将检测结果作为责令其限期治理的依据

下列哪项不是临床上加强支抗的方法

A．增加用作支抗牙齿的数目

B．使用方丝弓矫治技术

C．将支抗牙连成一整体而加强支抗作用

D．用口外唇弓来增强支抗

E．Nance弓

Many people are surprised when they find the Internet(因特网)was set up in the 1960s. At that time, computers were large and expensive. Computer networks(网络) didn’t work well. If one computer in the network broke down, then the whole network stopped. So a new network system (系统) had to be set up. It should be good enough to be used by many different computers. If a part of the network was not working, information could be sent through another part. In this way computer network system would keep on working all the time.
At first the Internet was only used by the government, but in the early 1970s,universities(大学) ,hospitals and banks were allowed(允许) to use it too. However, computers were still very expensive and the Internet was difficult to use. By the start of the 1990s, computers became cheaper and easier to use.
Today it is easy to get on-line(上网) and it is said that millions of people use the Internet every day. Sending e-mail is more and more popular among students.
The Internet has now become one of the most important parts of people’s life.

A good network system ______.

A. can keep on working
B. will stop working
C. will break down soon