Life on land probably began about 430 million years ago, though it has existed i
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Life on land probably began about 430 million years ago, though it has existed in the water for perhaps as much as 3,000 million years. When we think of the first thing on land, we probably think of strange animals coming out of the oceans, but in fact no animals could have been living if plants had not been on land first. Plants had to be on land before animals arrived. They supplied the first land animals with the surrounding and food necessity, since they, the plants, are the only form of life that is able to get and store energy.
The first plants to exist out of the water were probably certain kinds of algae（海藻）which were followed by other plants that grew close to the ground and needed water in which to reproduce. Once the move to land had been made, however, evolution（进化）took place quickly. By the end of 100 million years, plants had developed their roots（根）,and some had got tree -like forms since height was very important in gaining sunlight. About 300 million years ago, much of the world was covered with forests of huge trees. In most ways they were like modern trees. They had roots, leaves, wood, but mostly they had not developed seeds.
小题1:The main idea of the first paragraph is ________.| A．life on land probably began 430 years ago | | B．the first animal on land came from oceans | | C．there wouldn"t be animals without plants | | D．plants are the only form of life that is able to get and store energy |
小题2:Which of the following statements is true according to the passage?| A．Algae has existed for more than 430 million years. | | B．It is impossible that algae might be the earliest plant on land. | | C．Plants get food from animals in the oceans. | | D．Evolution began after animals appeared on land. |
小题3:Plants with roots appeared about ________ million years ago. 小题4:According to the passage, ________ appeared earlier than ________.| A．apples; oranges | B．oranges; apples | | C．oranges; roses | D．algae; wheat |
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答案
小题1:C
小题2:A
小题3:C
小题4:D |
解析
小题1:第一段有这句话：no animals could have been living if plants hadn’t been on land first.
小题2:第一段说陆地上的生命出现于430 million years ago，第二段说海藻是最早的植物。
小题3:最早出现的植物在四亿三千万年前，一亿年后植物开始生根，即三亿三千万年前。
小题4:从第二段最后可知，长根的植物比结子的植物要早,因此选D。 |
举一反三
The purpose of a letter of application is to help you to “sell” yourself. It should state 36 the job you want, and should tell what your abilities are and what you have 37 . It should be simple, human, personal and brief without 38 out any necessary fact.
In writing a letter of application, keep in 39 that the things a possible employer is most
40 to want to know about are your qualifications（条件）, your achievements and your aims.The opening paragraph is perhaps the most important part. 41 the first few sentences fail to 42 the reader’s attention, the rest of the letter may not be 43 at all. Try to key your opening remarks to the needs or interests of the employer not 44 your own need or desires. For example, instead of beginning with “I saw your 45 in today"s paper. ”you might say“I have made a careful 46 of your advertising during the past six months” or “I have made a survey in my neighbourhood to find out how many housewives 47 your product and why they like it.”
Try to 48 generalities. Be clear about the kind of job for which you are now 49 . College graduates looking for their first positions often ask“ What can I 50 in a letter? Employers want experience, which, naturally, no 51 has. ”The answer is that everything you have ever done is 52 .
It is important to write a good strong closing for your letter. 53 a specific request for an interview or give the possible employer something definite to do or expect. An excellent 54 is to enclose（内附）a stamped, self - addressed envelope with your letter. That makes it 55 for a possible employer to get in touch with you.
36．A. clearly B. carefully C. obviously D. easily
37．A. found B. done C. known D. heard
38．A. sending B. taking C. leaving D. picking
39．A. brain B. sight C. order D. mind
40．A. probable B. possible C. likely D. able
41．A. While B. Although C. As D. If
42．A. pay B. win C. show D. fix
43．A. kept B. continued C. written D. read
44．A. to B. for C. into D. from
45．A. advertisement B. report
C. article D. introduciton
46．A. watch B. search C. study D. discussion
47．A. change B. make C. sell D. use．
48．A. avoid B. remember C. protect D. gain
49．A. losing B. applying C. preparing D. fitting
50．A. offer B. supply C. mean D. provide
51．A. worker B. beginner C. owner D. manager
52．A. success B. development C. practice D. experience
53．A. Make B. Ask C. State D. Get
54．A. result B. decision C. promise D. idea
55．A. happier B. easier C. cheaper D. safer |
Plants are very important living things. Life could not go on if there were no plants. This is because plants can make food from air， water and sunlight. Animals and man cannot make food from air， water and sunlight. Animals get their food by eating plants and other animals. Therefore animals and man need plants in order to live. This is why we find that there are so many plants around us.
If you look carefully at the plants around you， you will find that there are two kinds of plants： flowering plants and non-flowering plants. Flowering plants can make seeds. The seeds are protected by the fruits. Some fruits have one seed， some have two， three or four， and some have many seeds. But a few fruits have no seeds at all. An example of a fruit without seeds is the banana fruit. Most non-flowering plants do not grow from seeds. They grow from spores（胚芽）。 Spores are very small. Some spores are so small and light that they can float in the air. We may say that spores are quite the same as seeds. When these spores are all on wet and shady places， they usually grow into new plants.
62.小题1:The main idea of the first paragraph is that ______.| A．plants are important for life | B．plants cannot grow without air | | C．there are many plants in the world | D．we can not live without water |
63.小题2:What can we infer（推断） from the passage ？| A．Of all living things animals are most. | B．Spores are seeds. | | C．All fruits of flowering plants have seeds. | D．Without plants，man will die out. |
64.小题3:What is the meaning of the underlined word?| A．Kept. | B．Guarded. | C．Prevented. | D．Surrounded |
65.小题4:This passage may be taken from______.| A．a medicine book | B．a novel | | C．a science magazine | D．an experiment report |
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For years scientists have been worried about the effects of air pollution on the earth’s natural conditions. Some believe the air inside many houses may be more dangerous than the air outside. It may be one hundred times worse.
Indoor air pollution can cause a person to feel tired, to suffer eye-pain, headache and other problems. Some pollutants（污染物） can cause breathing disorders, diseases of blood and even cancer, Most scientists agree that every modern house has some kind of indoor pollution. People began to notice the problem in the early 1970s. It is that when builders began making houses and offices they did not waste energy. To do this they built buildings that limited the flow of air between inside and outside. They also began using manmade building materials. These materials are now known to let out harmful gases. As the problem became more serious, scientists began searching for a way to deal with it. They discovered a natural pollution control system for building— green plants. Scientists do not really know how plants control air pollution. They believe that a plant’s leaves absorb or take in the pollutants. In exchange the plant lets out oxygen through its leaves and through its tiny organizations on its roots. Scientists suggest that all buildings should have one large plant or several small plants inside for every nine square metres of space. Studies of different plants show that each absorbs different chemicals. So the most effective way to clean the air is to use different kinds of plants. Having green plants inside your house can make it a prettier and more healthy place.
小题1:Generally speaking, indoor air pollution may be more harmful than the air outside because ________.| A．the man - made building materials let out dangerous gases inside houses | | B．there may be more harmful gases outside houses | | C．the flow of air indoors is limited | | D．indoor air pollution can make a person seriously ill |
小题2:The most effective way to clean the air is to use different kinds of plants because________.| A．they may let out more oxygen which people need | | B．they can absorb different kinds of the harmful indoor chemicals | | C．they can take in all kinds of indoor pollutants | | D．they can make your house prettier and more healthy |
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Of all living creatures on earth, insects are the most plentiful. Some 36 are very useful to man, for example, bees, 37 we get honey and wax, and silkworms, which 38 us with silk. Other varieties, 39 , are extremely harmful, and do a great 40 of damage, especially to crops. Locusts （蝗虫） are perhaps the most dangerous of all, 41 they will eat almost any green 42 , and when millions of them 43 on cultivated land（耕地）they soon leave it 44 . In some countries they are the farmer’s 45 enemy. Another nuisance is the common 46 , not only because it 47 us indoors and out - of- doors, but because it spreads diseases.
Scientists have given much time and 48 to the study of insects. It needs the most careful and 49 observation. Thanks 50 their discoveries we now know almost all 51 is to be known about the habits of these hardworking insects, bees and ants, which live in 52 better planned in some ways than our 53 . But the most valuable work has been done in trying to give 54 to men, animals and crops from the 55 which insects cause.
36．A. members B. forms C. qualities D. varieties
37．A. by which B. from which C. of which D. in which
38．A. give B. produce C. offer D. supply
39．A. however B. meanwhile C. therefore D. what"s more
40．A. majority B. number C. amount D. quantity
41．A. and B. for C. if D. when
42．A. grass B. field C. fruit D. plant
43．A. settle B. attack C. pass D. cross
44．A. bare B. nothing C. empty D. untouched
45．A. hardest B. greatest C. serious D. wildest
46．A. insect B. creature C. fly D. enemy
47．A. dislikes B. bites C. worries D. hates
48．A. understanding B. ideas C. comprehension D. thought
49．A. serious B. patient C. curious D. long
50．A. for B. of C. to D. with
51．A. that B. which C. there D. what
52．A. societies B. crowds C. teams D. organizations
53．A. world B. nation C. selves D. own
54．A. help B. protection C. living D. defense
55．A. injury B. wound C. sickness D. ruin |
For more than twenty years scientists have been searching for signs of life on other planets. Most of these searches have been done over the radio. The hope is that someone in outer space may be trying to get in touch with us. Scientists also have sent radio and television messages on spaceships traveling through space, on the chance that someone may be receptive to such messages.
Scientists are using powerful radio telescopes to listen to signals from about 1, 000 stars, all within 100 light years of earth. In addition, they will scan（扫视）the entire sky to “listen” for radio messages from more distant stars. Using a computer, they will be able to monitor more than eight channels at one time. Scientists are looking for any signal they stands out from the background noise.
Of the 200 billion stars in the Milky Way galaxy（银河星系）, scientists find that five percent are like our sun. Perhaps half of them have a planet like earth. Such a planet would be a reasonable distance from the star for temperatures to be right for the evolution（进化）of life. Based on the inhabitable（that can be lived in）planets in our galaxy, most scientists agree that chances are likely that one or more of these planets support some life.
However, many scientists wonder whether intelligent（有智力的）life exists on other planets. Some believe that twenty years of searching without any intelligible messages shows that no one is out there. They say that the evolution of intelligence comparable to ours is unlikely.
Other scientists believe that our search hasn’t been long enough to rule out the possibility that intelligent life exists in our galaxy. Although our sun family is only about five billion years old, our galaxy is about 20 billion years old. In that time, some scientists think it is likely that civilization（文明）much more advanced than ours have developed. Perhaps these civilizations send us no signals; perhaps we have not recognized the signals they have sent us. If we hope to find intelligent life, these scientists believe that we have to keep looking.
小题1:According to the passage, how many planets in our galaxy might be inhabitable?| A．5 billion． | B．10 billion. | | C．15 billion. | D．200 billion |
小题2:The first paragraph in this passage is mainly about ________ .| A．how scientists are looking for signs of life on other planets | | B．why scientists are looking for signs of life on other planets | | C．where scientists are looking for signs of life on other planets | | D．when scientists are looking for signs of life on other planets |
小题3:The underlined word “monitor” in the passage means“ ________ ”.| A．find | B．follow | | C．check | D．form |
小题4:Which of these statements is true based on the information in the passage?| A．The earth is one of the oldest planets in our galaxy. | | B．Most scientists believe that there is intelligent life on other planets. | | C．Scientists are trying different ways to find signs of life on other planets. | | D．Scientists don’t believe that there might be life on other planets. |
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