与聚氯乙烯管、聚乙烯管比较，无规共聚聚丙烯管的特点包括（）。 A．较好的耐磨性 B．

广义上的风险是指未来结果的不确定性，其中( )又被称为危险。

A．收益风险

B．纯粹风险

C．自然风险

D．投机风险

某猪场部分母猪不孕，后肢麻痹，或妊娠后4-12周发生流产，公猪出现睾丸炎或副睾炎，取病料涂片革兰氏染色镜检，见大量红色细胞。该病可能是：（）（602-30）

A、流行性乙型脑炎

B、布鲁氏菌病

C、猪繁殖与呼吸综合症

D、猪瘟

E、猪细小病毒病

阅读理解。

     PITTSBURGH-For most people, snakes seem unpleasant or even threatening. But Howie Choset

sees in their delicate movements a way to save lives.

     The 37-year-old Carnegie Mellon University professor has spent years developing snake-like robots

he hopes will eventually slide through fallen buildings in search of victims trapped after natural disasters

or other emergencies.

     Dan Kara is president of Robotics Trends, a Northboro, Mass.-based company that publishes an

online industry magazine and runs robotics trade shows. He said there are other snake-like robots being

developed, mainly at universities, but didn't know of one that could climb pipes.

     The Carnegie Mellon machines are designed to carry cameras and electronic sensors and can be

controlled with a joystick (操纵杆). They move smoothly with the help of small electric motors, or servos,

commonly used by hobbyists in model airplanes.

     Built from lightweight materials, the robots are about the size of a human arm or smaller. They can

sense which way is up, but are only as good as their human operators, Choset added.

     Sam Stover, a search term manager with the Federal Emergency Management Agency based in Indiana,

said snake-type robots would offer greater mobility than equipment currently available, such as cameras

attached to extendable roles.

     "It just allows us to do something we've not been able to do before," Stover said,"We needed them

yesterday."

     He said sniffer dogs are still the best search tool for rescue workers, but that they can only be used

effectively when workers have access to damaged building.

     Stover, among the rescue workers who handled the aftermath (后果) of Hurricane Katrina, said snake

robots would have helped rescuers search flooded houses in that disaster.

     Choset said the robots may not be ready for use for another five to ten years, depending on funding.

1. Which institution is responsible for the development of Choset's robots?

A. Robotics Trends.

B. Pittsburgh City Council.

C. Carnegie Mellon University.

D. Federal Emergency Management Agency.

2. Choset believes that his invention ______.

A. can be attached to an electronic arm

B. can be used by hobbyists in model airplanes

C. can find victims more quickly than a sniffer dog

D. can sense its way no better than its operators

3. By saying "We needed them yesterday" (paragraph 7), Stover means that snake-like robots _____.

A. could help handle the aftermath of Hurricane Katrina

B. would have been put to use in past rescue work

C. helped rescuers search flooded houses yesterday

D. were in greater need yesterday than today

4. What is the text mainly about?

A. Snake-like robots used in industries.

B. Snake-like robots made to aid in rescues.

C. The development of snake-like robots.

D. The working principles of snake-like robots.

对粘膜下注射法治疗脱肛的描述不正确的是：（）

A.机制是使分离的直肠粘膜与肌层粘连固定

B.分为点状注射和柱状注射

C.注射当天适当休息

D.对Ⅰ度直肠脱垂效果最好

E.在齿线上2cm处注射

直流电气设备的正极连线导线为（）色。

A.红色

B.黑色

C.褚色

D.蓝色