问题 单项选择题

信息安全主要从四个方面保证计算机系统和通信系统的正常运作,以下不属于这四个方面的是

A.保密性

B.完整性

C.可控性

D.潜伏性

答案

参考答案:D

解析: 信息安全从简单的意义来理解,就是要防止非法的攻击和病毒的传播,以保证计算机系统和通信系统的正常运作。而从更全面的意义来理解,就是要保证信息的保密性、完整性、可用性和可控性。综合起来,就是要保障电子信息的有效性。

多项选择题
阅读理解

Did you ever wonder how some of your favorite foods, products or toys came about? Believe it or not, they may have been an accident, or a failure of some other intention. Below, we found three mistakes we’re thankful for turned out to be what they are.

1. Most historians hold that the Chinese invented fireworks in the 9th century when they

discovered how to make gunpowder. Story has it that a Chinese cook accidentally mixed together what were then considered common kitchen items and noticed they burnt. When put tightly in a bamboo tube and lit, it blew up.

2. In May of 1886, a law led John Pemberton, a pharmacist(药剂师), to rewrite the formula(配方) for "Pemberton’s French Wine Coca,” his popular headache treatment. Containing sugar instead of wine as a sweetener, the outcome became something for Coke, which was later mixed with carbonated water. His bookkeeper suggested the name Coca-Cola because he thought the two C’s would look good together, which is how what we call Coca-Cola, a world –wide drink came into being.

3. During World War II, scientists at the University of Birmingham invented the magnetron—an important heat-producing part of the microwave oven(微波炉). While working for Raytheon Corporation after the war, the American engineer Percy Spencer was testing the magnetron when a chocolate bar in his pocket melted. He went on to test other foods including popcorn kernels, and found it to be a much more efficient way to cook. In 1947 Raytheon came out with the first restaurant microwave oven, which was six feet tall and weighed 750 lbs.   

小题1:The right time order of the three inventions, according to the passage, should be_________.

A.fireworks, the microwave and Coca-Cola

B.fireworks ,Coca-Cola and the microwave

C.Coca-Cola , fireworks and the microwave

D.the microwave, Coca-Cola and fireworks小题2:Percy Spencer found the microwave efficient in cooking when he was _______.

A.looking for a way to melt his chocolate

B.trying to know how a magnetron could cook

C.working to know how the magnetron works

D.asked to invent a restaurant microwave oven小题3:What can we learn from the above invention stories? 

A.Experiments make great inventors of our time.

B.Nothing is impossible if one tries each day.

C.Inventors come out of hard work at any time.

D.A small incident may lead to a great invention.小题4:What’s the best title for the passage?

A.What great inventions they are!

B.Inventions from Three Countries.

C.Stories of Accidental Inventions.

D.The Human Inventions of time.