If you and your friends wish to share a secret, you can write it in code, and no one else will be able to read it. Codes are one way of writing in secret. Ciphers (密码) are another. In a code each word is written as a secret code word or code number. In a cipher each letter is changed.

Codes and ciphers have played an important role in the history of the world. Julius Caesar, the Roman ruler who defeated almost all the countries in Europe about 2, 000 years ago, used a cipher when he sent secret messages to his troops. During the American Revolution, George Washington's spies used a kind of code to send him information about the enemy before his military action. In World War Ⅱ, the Americans "broke", or figured out, Japan's most important naval codes and got enough information to destroy a powerful Japanese fleet(舰队).

Storekeepers use codes to mark their goods. The codes show how much was paid for the goods or when they were added to the stock. Businessmen use codes to hide plans from their business enemies. Sometimes personal letters or diaries are written in code. Many people enjoy figuring out codes and ciphers simply as a hobby.

In the 16th century, codes and ciphers were very popular among scientists. They wrote messages to each other in code so that no one else would learn their secrets. Geronimo Gardano, an Italian astrologer(占星家), mathematician, and doctor, invented the trellis cipher. He took two sheets of paper and cut exactly the same holes in each one. Then he sent one sheet, which he called a trellis, to a friend and kept the other for himself. Whenever he wanted to write a message, he put his trellis over a clean sheet of paper and wrote the secret message through the holes. Then he removed the trellis and filled the rest of the paper with words that would make sense. When his friend received it, he put his trellis over the writing and read the secret message.

1. What does the underlined word "trellis"mean?

A. A piece of paper with many small holes.

B. A machine with a lot of small holes.

C. A letter with unreadable words and sentences.

D. A sheet of paper with groups of Arabic figures.

2. Which of the following statements is true?

A. Ciphers can be broken or figured out more easily than codes.

B. You could read some words in Geronimo' s letter without his trellis.

C. The first person who ever used a cipher in history was Julius Caesar.

D. Fondness of using codes was the hobby of the scientists in the 16th century.

3. The best title of this passage is________.

A. Codes and Ciphers

B. Differences between Codes and Ciphers

C. History of Codes and Ciphers

D. Inventors of Codes and Ciphers

From the earliest times men seem to have noticed the habits of insects, and to have learnt lessons from them. Ants and bees work very hard the summer, __1__enough food to last the winter. They set us a good example to__2__. If we waste time when the conditions are good for work, we shall probably__3__later; when we really want to work, we are__4__ to do so. Moths(蛾), and some other insects, cannot help flying__5__a light of any kind. The attraction seems to be too strong for them. As a result, they often__6__ themselves by flying into something that is burning, such as a lighted candle. In some countries, when such insects as flying ants become a nuisance(讨厌的东西), people__7__themselves by lighting fires at the doors of their cottages. Sometimes the insects fly into the fire in such large__8__ that they put it out. In literature we often find poets warning us of the danger of being attacked by__9__or beautiful things that will destroy us. Butterflies are admired for their __10__,though they receive very little praise for anything else. They fly__11__in the sunshine, going from flower to flower, happy all day long, leading a life of __12__.They are beautiful, but it seems that they are not of much__13__use to anybody. Some human beings lead very much the same sort of life__14__they are butterflies of society. Locusts(蚱蜢) are__15__. They are active enough, too active. They spend their time eating the food of others. __16__there are men like this, destroying things wherever they go, taking for themselves __17__belongs to others, using up everything and__18__nothing. They are human__19__. Perhaps it may be said that even the worst insects have one use:they__20__us not to be like them.

1. A. planting B. losing C. collecting D. growing

2. A. learn B. follow C. see D. accept

3. A. work B. realize C. suffer D. miss

4. A. anxious B. unnecessary C. nervous D. unable

5. A. towards B. from C. into D. away

6. A. destroy B. benefit C. give D. help

7. A. prevent B. keep C. protect D. escape

8. A. teams B. numbers C. groups D. lines

9. A. bright B. burning C. dirty D. lighting

10. A. size B. strength C. beauty D. work

11. A. about B. up C. down D. high

12. A. sadness B. pleasure C. business D. disability

13. A. real B. true C. greatly D. badly

14. A. but B. and C. or D. though

15. A. different B. similar C. blind D. honest

16. A. Luckily B. Immediately C. Unfortunately D. Scarcely

17. A. that B. which C. who D. what

18. A. preparing B. eating C. storing D. producing

19. A. locusts B. moths C. enemies D. butterflies

20. A. tell B. advice C. warn D. ask

Humans are social animals. They live in groups all over the world. As these groups of people live apart form other groups, over the years and centuries they develop their own habits and ideas, which from different cultures. One important particular side of every culture is how its people deal with time.

Time is not very important in nonindustrial societies. The Nuer people of East Africa, for example, do not even have a word TIME that is in agreement with the abstract thing we call time. The daily lives of the people of such nonindustrial societies are likely to be patterned around their physical needs and natural events rather than around a time schedule(时间表) based on the clock. They cook and eat when they are hungry and sleep when the sun goes down. They plant crops during the growing seasons and harvest them when the crops are ripe. They measure time not by a clock or calendar(日历), but by saying that an event takes place before or after some other event. Frequently such a society measures days in terms of "sleeps" or longer periods in terms of "moons". Some cultures, such as the Eskimos of Greenland measure seasons according to the migration(迁徙) of certain animals.

Some cultures which do not have a written language or keep written records have developed interesting ways of "telling time". For example, when several Australian aborigines(土著居民) want to plan an event for a future time, one of them places a stone on a cliff or in a tree. Each day the angle of the sun changes slightly. In a few days, the rays of the sun strike the stone in a certain way. When this happens, the people see that the agreed-upon time has arrived and the event can take place.

In contrast(成对比), exactly correct measurement of time is very important in modern, industrialized societies. This is because industrialized societies require the helpful efforts of many people in order to work. For a factory to work efficiently (well, quickly and without waste),for example, all of the workers must work at the same time. Therefore, they must know what time to start work in the morning and what time they may go home in the afternoon. Passengers must know the exact time that an airplane will arrive or depart. Students and teachers need to know when a class starts and ends. Stores must open on time in order to serve their customers. Complicated (复杂的) societies need clocks and calendars. Thus, we can see that if each person worked according to his or her own schedule, a complicated society could hardly work at all.

7. By saying "Humans are social animals",the author means________.

A. they live all over the world

B. they are different from other animals

C. they live in one place, district or country, considered as a whole

D. they are divided into many groups

8. Time is not very important in non-industrial societies, because peoplein those societies________.

A. don't have the word TIME in their languages

B. don't get used to using clocks and other timepieces

C. don't measure time in their daily lives around an exact time schedule

D. don't need to plan their daily lives around an exact time schedule

9. The Australian aborigines' way of"telling time" is based on________.

A. the change of the sun rays

B. the movement of the earth in relation to the sun

C. the position of the stone

D. the position of the tree or the cliff

10. Which of the following might be the best title for this passage?

A. Time and Culture

B. The Measurment of Time

C. Time Schedule and Daily Life

D. Clock,Calendar and Society

Place a piece of dark metal and a piece of light-coloured wood or cloth of about the same size side by side in the sunlight on a bright afternoon. Touch them after a while, or set a thermometer on each. You will find the dark metal is hotter, though both have been warmed by the sun for the same length of time. This is because some things absorb(吸收) more heat from the sun than others, lying in their colour, form and material. A ploughed field of black soil becomes heated faster than a field of corn. The cornfield in turn absorbs more heat than a lake or a pond. This curious fact about heating explains the most common thunderstorms(雷雨), the kind seen on a summer afternoon.

4. From the passage we know________.

A. the colour of wood or cloth is lighter than that of metal

B. if you stand in a cornfield you'll feel hotter than in a ploughed field

C. when the sunlight is not quite bright light-coloured wood absorbs more heat than dark metal

D. if you put something in the sun, its temperature will be affected by its color, form and material

5. The underlined word "thermometer"probably means________.

A. something that is like a stove

B. an instrument for measuring temperature

C. a tool which is used to heat

D. a watch which can be started and stopped

6. The last sentence of the passage leads us to conclude that________.

A. thunderstorms break out over a lake

B. thunderstorms have something to do with the heat from the sun

C. thunderstorms are often seen in winter, too

D. thunderstorms have never happened in dark materials

We have seen that pesticides(杀虫剂)now pollute soil, water, and food, and that they have the power to make our rivers fishless and our gardens and woodlands silent and birdless. Man, however much he may like to pretend the opposite, is part of nature. Can he escape a pollution that is now so thoroughly spread throughout our world?

We know that even single exposure(暴露) to these chemicals, if the amount is large enough, can cause extremely severe poisoning. But this is not the major problem. The sudden illness or death of farmers, farm workers, and others exposed to enough quantities of pesticides is very sad and should not happen. For the population as a whole, we must pay more attention to the delayed effects of taking in small amounts of the pesticides that unseeably pollute our world.

Responsible(负责的) public health officials have pointed out that the biological effects of chemicals are increasing in amount over long periods of time, and that the danger to man may depend on the amount of the exposures received throughout his lifetime. For these very reasons people easily take no notice of the danger. It is human nature to shake off what may seem to us a future disaster(灾害). "Men are naturally most impressed by diseases which have obvious signs," says a wise physician, Dr. Rene Dubos, "yet some of their worst enemies slowly come near them unnoticed."

1. Which of the following is closest in meaning to the underlined sentence?

A. Man doesn't care about what happens in nature.

B. Man acts as if he does not belong to nature.

C. Man can avoid the effects of environmental pollution.

D. Man can escape his responsibilities for environmental protection.

2. People are likely to take no notice of the delayed effects of exposure to chemicals because________.

A. limited exposure to them does little harm to people's health

B. the present is more important to them than the future

C. the danger does not become seen clearly and immediately

D. humans are able to bear small amounts of poisoning

3. It can be concluded from what Dr. Dubos says that________.

A. people find hidden diseases difficult to deal with

B. attacks by hidden enemies are likely to be deadly

C. diseases with obvious signs are easy to cure

D. people are likely to take no notice of hidden dangers caused by pesticides

Our country has many chances for adults who want to make their lives better. There are public schools you can attend. In the schools, you can take things__1__English, arithmetic and history, you can find classes in almost__2__subject you want to study. You may want to__3__to type, sew, paint or fix TV sets. You may want to learn __4__about the trade you are already in. You may want to get a high school diploma(文凭). You may__5__want to go to college. All it takes is time and effort. In many cities, there are adult classes in__6__schools. You can attend many of these classes without__7__to pay money. In some schools you may have to pay a small fee. There are__8__many kinds of private schools for adults, where you may have to pay more money. Many job chances are __9__to those who wish to work. It helps if you know__10__than one language. There are good__11__for interpreters and typists who know English. There are many good jobs in government. In most cases, you must be a citizen of this country, and you must__12__a civil service examination. These examinations are__13__to everyone, regardless of(不管) race, religion or colour. For many civil service jobs you __14__a high school diploma. The person who does not have a high school diploma can get__15__. There are several ways. You can study high school__16__at home and then take special tests. __17__you pass the tests, then you get a diploma. Or you can go to a night school. There are classes that__18__you to take special tests to get a diploma. Be as well trained as you can. Get as much training as you can. __19__knocks at every door. Be sure that when it knocks at your door you are__20__.

1. A. like B. in C. of D. as

2. A. some B. any C. all D. either

3. A. teach B. examine C. learn D. begin

4. A. what B. more C. again D. others

5. A. perhaps B. never C. very D. even

6. A. middle B. high C. public D. private

7. A. regretting B. agreeing C. having D. beginning

8. A. still B. also C. almost D. such

9. A. chosen B. allowed C. promised D. offered

10. A. better B. more C. fewer D. less

11. A. jobs B. schools C. works D. wishes

12. A. take B. join C. hold D. give

13. A. possible B. open C. limited D. permitted

14. A. want B. get C. demand D. need

15. A. none B. one C. them D. that

16. A. subjects B. classes C. tests D. English

17. A. Until B. First C. If D. Though

18. A. make B. permit C. lead D. prepare

19. A. Text B. Job C. Diploma D. Chance

20. A. prepare B. ready C. studying D. working

 Can it be in the restaurant ______ you had dinner with me yesterday that you left behind your

keys and wallet?

A. why                        B. where                      C. that;                  D. when

 ______ good, the food was soon sold out.

A. Tasted                   B. Being tasted             C. Tasting           D. Having tasted

 Your sister is said ______ in the supermarket when she was doing shopping yesterday.

A. to be treated badly                                        B. treating badly   

C. being badly treated                                       D. to have been badly treated

 When you rewrite the paragraph, I advise you to ______ the last sentence as it is rather

misleading.

A. work out              B. leave out                C. point out          D. pick out