问题 选择题
2002年诺贝尔物理学奖中的一项,是奖励美国科学家贾科尼和日本科学家小柴晶俊发现了宇宙X射线源.X射线是一种高频电磁波,若X射线在真空中的波长为λ,以h表示普朗克常量,c表示真空的光速,以E和m分别表示X射线每个光子的能量和质量,则(  )

A.E=,m=0

B.E=,m=

C.E=,m=0

D.E=,m=

答案

答案:D

阅读理解

阅读理解

      Imagine this: a television screen has the size and thickness of a piece of paper. You carry it around in

your pocket and take it out when you want to watch a show. Imagine a guitar so tiny that you can't see it

with the human eye, but you can hear sound when its strings are pulled.

      Nanotechnology (纲米技术)  is the science that deals with doing things in a very small way, and it is

being studied and developed all over the world. Many scientists say nanotechnology will produce the next

industrial revolution (工业革命) .

      Perhaps nanotechnology will have the biggest influence on medical science. Imagine manobots (纲米机器人) in medicine. Thousands or even millions of tiny machines can be sent into the human body with

specific tasks. For example, they can be designed to find and destroy cancer cells or viruses (病毒). Other machines may stay in the human body for ever to help organs (器官) that are not working properly.

      When could all of these happen? Scientists predict that most of these are possible in the next 30 years. Thousands of scientists around the world are working on these micro - machines.  Nanotechnology is just around the corner.

1. The two examples in Paragraph l are used to __________            

A. introduce the smallest television            

B. introduce a new kind of guitar            

C. introduce the topic of the passage

2. Nanotechnology ___________            

A. will cause an industrial revolution            

B. deals with things in old ways            

C. has studied the whole world

3. The underlined word "they" in the third paragraph refers to (指代)________            

A. scientists          

B. human bodies            

C. tiny machines

4. The tiny machines _____________          

A. are too small to be repaired            

B. can be put in a human body to kill viruses            

C. may not work well in a human body

5. The underlined phrase "around the corner" in the last sentence means"_________"          

A. far away  

B. at present      

C. in the near future

单项选择题