When you think about math, you probably don’t think about breaking the law, solving mysteries or finding criminals. But a mathematician in Maryland does, and he has come up with mathematical tools to help police find criminals.

　　People who solve crimes look for patterns that might reveal (揭示) the identity of the criminal. It’s long been believed, for example, that criminals will break the law closer to where they live, simply because it’s easier to get around in their own neighborhood. If police see a pattern of robberies in a certain area, they may look for a suspect who lives near the crime scenes. So, the farther away from the area a crime takes place, the less likely it is that the same criminal did it.

　　But Mike O’Leary, a mathematician at Towson University in Maryland, says that this kind of approach may be too simple. He says that police may get better clues to the location of a criminal’s home base by combining these patterns with a city’s layout (布局) and historical crime records.

　　The records of past crimes contain geographical information and can reveal easy targets — that is, the kind of stores that might be less difficult to rob. Because these stores are along roads, the locations of past crimes contain information about where major streets and intersections are. O’Leary is writing a new computer program that will quickly provide this kind of information for a given city. His program also includes information about the people who live in the city, and information about how a criminal’s patterns change with age. It’s been shown, for example, that the younger the criminal, the closer to home the crime.

　　Other computer programmers have worked on similar software, but O’Leary’s uses more math. The mathematician plans to make his computer program available, free of charge, to police departments around the country.

　　The program is just one way to use math to fight crime. O’Leary says that criminology — the study of crime and criminals — contains a lot of good math problems. “I’m the only one who knows what gold looks like,” he says. “It’s a lot of fun.”

　　49. To find criminals, police usually _________.

　　A. check who are on the crime scene

　　B. seek help from local people

　　C. depend on new mathematical tools

　　D. focus on where crimes take place

　　50. O’Leary is writing a computer program that _________.

　　A. uses math to increase the speed of calculation

　　B. tells the identity of a criminal in a certain area

　　C. provides the crime records of a given city

　　D. shows changes in criminals’ patterns

　　51. By “I’m the only one who knows what gold looks like”, O’Leary means that he _________.

　　A. is better at finding gold than others

　　B. is the only one who uses math to make money

　　C. knows best how to use math to help solve crimes

　　D. has more knowledge of gold than other mathematicians

　　52. What is the main idea of the text?

　　A. Math could help police find criminals.

　　B. Criminals live near where crimes occur.

　　C. Crime records could be used to fight crime.

　　D. Computer software works in preventing crimes.

阅读下面短文, 掌握其大意, 然后从1～25各题所给的四个选项中, 选出一个最佳答案。　　

    In the western world's largest 1 plant, which pours 1,000 tons of steel every hour, thirty-four-year-old Ray Bagrosky, works as an electrical helper. Bagrosky is one of a team which repairs motors for the Bethichen Steel Plant in Baltimore, Maryland. He has been there about a year, and he 　　 2 the work. "I get dirty," he admitted. "but I enjoy 3 things and making them 4 right."　　

    Ray left high school a year 　　 5 graduation and joined the Navy (海军)  Seven months at Navy schools for electricians 6 and then more than three years sea duty, which took him into the South China Sea and the Indian Ocean as well as the Pacific. Eighteen months before his tour of duty was completed, he 　　 7 Margaret Lamr, a pretty girl, from his neighbourhood whom he had　　 8 ten years. They 9 have two small sons.　　

    Ray's day begins at 5:30 A.M. When he gets up, dresses himself, and ten minutes 　　 10 he jumps into his car and begins his daily 11 to the　　 factory. "Traffic's heavy", he once said, "so Margrate 12 my breakfast　　 in my lunchbox and I 13 it when I get to work. "　　 14 seven he is at work on whatever job is to be 15 with a half an hour for 　　 16, he works until 3:30 P.M.　　 Soon after four 17, Ray gets home 　　 18 to a two-story red brick house on a quiet street 19 with trees and grass. He showers and puts on 20 clothes.　　

    The neighbors exchange conversation on their front porches (门廊), dogs play and children ride their bicycles and call 21 to each other at their games. The Bagroskys live quietly. They take pleasure from an outing on her father's small powerboat, a swim, a movie, or a football　　 game. Ray keeps a 22 eye on newspaper headlines (新闻提要)  Because he　　 works for a huge company and owns possessions, he watches what 　　 23 in the nation and in his own 24. And because he still has friends in the Navy, he is interested in 25 is happening in the world.　　

　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　 　　

(1)	A. still	B. oil	C. steel	D.truck	［　　］
(2)	A. likes	B. hates	C. dislikes	D.looks down upon	［　　］
(3)	A. driving	B. producing	C. controlling	D.repairing	［　　］
(4)	A. stop	B. run	C. begin	D.go	［　　］
(5)	A. after	B. before	C. when	D.since	［　　］
(6)	A. spent	B. took	C. followed	D.cost	［　　］
(7)	A. married	B. engaged	C. fell in love	D.got	［　　］
(8)	A. known	B. realized	C. looked after	D.brought up	［　　］
(9)	A. then	B. only	C. thus	D.now	［　　］
(10)	A. ago	B. later	C. earlier	D.before	［　　］
(11)	A.hour	B. work	C. trip	D.job	［　　］
(12)	A. carries	B.prepared	C.took	D.puts	［　　］
(13)	A. take	B. carry	C. make	D.eat	［　　］
(14)	A. Till	B. By	C. After	D.Until	［　　］
(15)	A. over	B. done	C. worked	D.got	［　　］
(16)	A. lunch	B. breakfast	C. supper	D.dinner	［　　］
(17)	A. hours	B. minutes	C. o'clock	D.times	［　　］
(18)	A. still	B. even	C. again	D.also	［　　］
(19)	A. lined	B. lining	C. surrounded	D.surrounding	［　　］
(20)	A. clean	B. dirty	C. new	D.rejected	［　　］
(21)	A. slowly	B. exciting	C. loudly	D.happy	［　　］
(22)	A. sleep	B. careful	C. stared	D.glaring	［　　］
(23)	A. gets	B. takes place	C. goes on	D.breaks out	［　　］
(24)	A. house	B. city	C. family	D.country	［　　］
(25)	A. that	B. where	C. something	D.what	［　　］

短文改错

That evening I was doing my lesson. It was about　　   1．________　　

9 o'clock. I heard strange noise which sounded　　   2．________　 

like the flowing of water. Suddenly I found the　　　  3．________　

 walls shaking as if someone was pushing it. Thinking  4．________

perhaps I was such tired, I stood up, and was going    5．________

to bed. Just then I heard someone to shout “Earth－   6．________　

quake!” The word put much fear into everyone heart.　 7．________　

 I rushed out of the house as quick as possible. The 　8．________

whole street was already filled up people. I felt　　  9．________　　

everything was trembling. The earthquake last a few    10．________

 seconds. Then everything was quiet again.