显影温度一般应控制在什么范围？

X摄片中，四肢骨的摄片距离通常多用()

A．140cm

B．100cm

C．70cm

D．60cm

E．50cm

判断下面说法的正误，在括号中打“√”或“×”。

1、《白杨礼赞》是一篇抒情散文。文章运用象征手法，托物抒情，借白杨树的形象，赞美在中 * * 党领导下坚持抗战的北方农民，质朴、坚强、力求上进的精神，抒发了作者对抗日军民的崇敬之情。（ ）

2、象征与比喻、拟人不同。象征是文艺创作的一种表现手法，是通过某一特定的具体事物（即象征物）来表现与之有某种联系的概念、思想和感情（即象征义），从而使抽象的情理形象化，使所要表达的意思更含蓄、更深刻。因此象征是就篇章而言的，而比喻、拟人是修辞方法，只表现在具体的句子上，不在篇章上。（ ）

3、《白杨礼赞》是以赞美白杨树的不平凡为全文的主线的。（  ）

4、《白杨礼赞》作者是杨朔，我国现代作家。（  ）

我国将全面禁止使用含铅汽油，其主要目的是：

A．减少汽车尾气中氮氧化物的排放量

B．提高汽油的燃烧值

C．消除汽车尾气中的铅对大气的污染

D．使汽油燃烧得更充分

患者胞睑内生硬结半年，皮色如常，按之不痛，与睑皮肤不粘连

最可能的病因是（）

A.痰湿阻结

B.痰热阻结

C.恣食炙博厚味

D.外感风寒

E.外感风热

Internet is a vast network of computers that connects many of the world’s businesses, institutions, and individuals. (46) The Internet, which means interconnected network of networks, links tens of thousands of smaller computer networks. These networks transmit huge amounts of information in the form of words, images, and sounds.

The Internet has information on every topic.(47)Network users can search through sources ranging from vast databases to small electronic" bulletin boards", where users form discussion groups around common interests. Much of the Internet’s traffic consists of messages sent from one computer user to another. These messages are called electronic mail or e-mail. Internet users have electronic addresses that allow them to send and receive e-mail. Other uses of the network include obtaining news, joining electronic debates, and playing electronic games.(48)One feature of the Internet, known as the World Wide Web, provides graphics, audio, and video to enhance the information in its documents. These documents cover a vast number of topics.

People usually access the Internet with a device called a modem. Modems connect computers to the network through telephone lines. Much of the Internet operates through worldwide telephone networks of fiber-optic cables(49) These cables contain hair-thin strands of glass that carry data as pulses of light. They can transmit thousands of times more data than local phone lines, most of which consist of copper wires.

In the future, the internet will probably grow more sophisticated as computer technology becomes more powerful. (50)Many experts believe the Internet may become part of a larger network called the information superhighway. This network, still under development, would link computers with telephone companies, cable television stations, and other communication systems. People could bank, shop, watch TV, and perform many other activities through the network.

(48)One feature of the Internet, known as the World Wide Web, provides graphics, audio, and video to enhance the information in its documents.