It began as a game: high school and college students studying computer technology figured out (领会到，想象出来) they could use personal computers to break into (闯入) telephone company computers and make free, long-distance telephone calls. These young computer wizards (奇才) soon gained the nickname "hackers (黑客)".

Police put the collar on (拘留，逮捕) a few hackers, but many went on to even more complex hacking. One hacker was arrested for making illegal telephone calls and later used a jailhouse (监狱) phone to alter (变更) a police officer's credit records (信用记录) to get back at (报复) the officer for arresting him. The hacker also used a computer to alter his college records to give himself better grades.

As hackers gained experience, they began invading (侵入) computers at banks, airlines and other businesses. In one scheme (计划，方案), a hacker instructed an airline's computer to give him free airplane tickets.

The U.S. government is worried hackers may break into its sophisticated (复杂的，尖端的) networks of defense computers. The government's classified (分类的) secrets are vulnerable (脆弱的) because thousands of government computers are connected by telephone lines that hackers can tap into (敲入，进入).

In November 1988, a college student tapped into a non-classified U.S. Defense Department computer network called Arpanet. The hacker injected (输入，注入) a computer program that left copies of itself throughout Arpanet. Some hackers use each "viruses (病毒)" to destroy all the data in a computer. But in this case, government officials shut down the network before the program reached every computer in the system. Shutting down the system angered many researchers who were using the computers. The hacker turned himself in (自首) to police and told them how to get his program out of the computer system. He was charged with a crime.

The incident put the spotlight on (引起注意) computer hacking in the United States. Many companies have hired experts to protect their computers from hackers, and many computer experts now advise companies on how to protect their computers.

The U.S. government believes foreign governments have hired hackers to try to break into top-secret (绝密的) defense computers. It fears a hacker could inject a virus into military computers that would erase all the data during a war.

Experts disagree over whether a computer network can ever be safe from hacking. But in the future, some of the most brilliant (杰出的，卓越的) minds in the U.S. will be working to frustrate (挫败) the efforts of computer hackers and spies.

Choose the correct answer.

1. The main idea of the article is _____.

A. computer hackers only want to make free long-distance phone calls

B. the government wants to hire computer hackers to spy on the Russians

C. computer hackers are a threat to private companies and government secrets

D. many companies have hired experts to protect their computers from hackers who carry viruses

2. A computer "virus" is like a human virus because it _____.

A. makes a computer cough and throw up

B. spreads from one computer to other computers

C. can erase a person's doctor bills

D. requires regular visits to a doctor

3. A hacker can be dangerous because _____.

A. he knows how to make free long-distance telephone calls

B. vital information is stored in computers, and a hacker knows how to change or erase the information

C. once in jail, he can use a telephone to operate his computer

D. a hacker who steals a free airplane ticket might deprive a doctor of that seat on the airplane

4. U.S. government computers are vulnerable to a hacker because _____.

A. the government always pays its telephone bills on time

B. the Russians know what's in the U.S. computers

C. viruses attack only government computers

D. many government computers are connected by telephone lines

5. In the future _____.

A. Some of the most brilliant minds in America will be working to try to stop computer hackers and spies

B. hackers will begin invading computers at banks, airlines and other businesses

C. many computer hackers will be arrested for making free telephone calls

D. some computer hackers will turn themselves in to the police

Keys: CBBDA