Which is safer-staying at home， traveling to work on public transport， or working in the office? Surprisingly， each of these carries the same risk， which is very low. However， what about flying compared to working in the chemical industry? Unfortunately， the former is 65 times riskier than the latter! In fact， the accident rate of workers in the chemical industry is less than that of almost any of human activity， and almost as safe as staying at home.

The trouble with the chemical industry is that when things go wrong they often cause death to those living nearby. It is this which makes chemical accidents so newsworthy. Fortunately， they are extremely rare. The most famous ones happened at Texas City (1947)，Flixborough (1974)， Seveso (1976)， Pemex (1984) and Bhopal (1984)。

Some of these are always in the minds of the people even though the loss of life was small. No one died at Seveso， and only 28 workers at Flixborough. The worst accident of all was Bhopal， where up to 3，000 were killed. The Texas City explosion of fertilizer killed 552. The Pemex fire at a storage plant for natural gas in the suburbs of Mexico City took 542 lives， just a month before the unfortunate event at Bhopal.

Some experts have discussed these accidents and used each accident to illustrate a particular danger. Thus the Texas City explosion was caused by tons of ammonium nitrate(硝酸铵)，which is safe unless stored in great quantity. The Flixborough fireball was the fault of management， which took risks to keep production going during essential repairs. The Seveso accident shows what happens if the local authorities lack knowledge of the danger on their doorstep. When the poisonous gas drifted over the town， local leaders were incapable of taking effective action. The Pemex fire was made worse by an overloaded site in an overcrowded suburb. The fire set off a chain reaction os exploding storage tanks. Yet， by a miracle， the two largest tanks did not explode. Had these caught fire， then 3，000 strong rescue team and fire fighters would all have died.

1.Chemical accidents are usually important enough to be reported as news because ____.

A.they are very rare

B.they often cause loss of life

C.they always occur in big cities

D.they arouse the interest of all the readers

2.Which of the following statements is true?

A.Working at the office is safer than staying at home.

B.Traverlling to work on public transport is safer than working at the office.

C.Staying at home is safer than working in the chemical industry.

D.Working in the chemical industry is safer than traveling by air.

3.According to passage， the chemical accident that caused by the fault of management happened at ____.

A.Texas city B.Flixborough C.Seveso D.Mexico City

4.From the discussion among some experts we may coclude that ____.

A.to avoid any accidents we should not repair the facilities in chemical industry

B.the local authorities should not be concerned with the production of the chemical industry

C.all these accidents could have been avoided or controlled if effective measure had been taken

D.natural gas stored in very large tanks is always safe

5.From the passage we know that ammonium nitrate is a kind of ____.

A.natural gas， which can easily catch fire

B.fertilizer， which can't be stored in a great quantity

C.poisonous substance， which can't be used in overcrowded areas

D.fuel， which is stored in large tanks

Questions 1 to 5 are based on the following passage:

Some years ago the captain of a ship was very interested in medicine. He always took medicine books to sea and liked to talk about different diseases.

One day a lazy sailor on his ship pretended to be ill. He lay on his bunk (铺) and groaned as if he were very sick. The captain came to see him and was very pleased to have a patient to look after. He told the man to rest for a few days and made the other sailors do his work. Three days later another sailor pretended that he had something wrong with his chest. Once more the captain looked in his medical books and told “sick” man to have a rest.

The other sailors were very angry because they had more work to do. The patients had the best food and laughed at their friends when the captain was not looking. At last the mate (船长副手) decided to cure the “sick” men. He mixed up some soap, soot (烟灰), glue (胶水) and other unpleasant things. Then he obtained permission from the captain to give his medicine to the “sick” men. When they tasted the medicine, they really did feel ill. It was so horrible that one of the patients jumped out of hi bunk, ran up on desk and climbed the highest mast on the ship. He did not want any more medicine.

The mate told both of the men that they must take the medicine every half an hour, night and day. This soon cured them. They both said they felt better and wanted to start word again. The captain realized that the men tried to deceive him so he made them work very hard for the rest of the voyage.

1. The first sailor pretended to be ill because he wanted to .

A. test the captain’s knowledge of medicine 

B. be free from work

C. have the best food on the ship

 D. play a joke on his friends

2. When the captain knew a sailor was ill, he .

A. didn’t care much 

B. sent for a doctor

C. looked after him and told him to have a rest

D. gave him some medicine

3. The patients felt better quickly because .

A. they had been given proper medicine

B. they learned that the captain had found out the truth

C. they were laughed at by their friends

D. the medicine the mate gave was horrible

4. When the captain knew he had been deceived, he .

A. told them not to do so again 

B. lost his temper

C. made them work harder 

D. fired them

5. Which of the following best summarizes the passage?

A. A sudden Cure. 

B. Two Patients. 

C. Captain and Sailors. 

D. A Difficult Voyage.

Passage4

Questions16to20arebasedonthefollowingpassage:

Thenewglobalsatellitecommunicationssystemswillofferthreekindsservice,whichmayoverlapinmanydifferentkindsofreceivers.

VOICE.SatellitetelephoneswillbeabletomakecallsfromanywhereontheEarthtoanywhereelse.Thatcouldmakethemespeciallyusefultoremote,thirdworldvillages(someofwhichalreadyusestationarysatellitetelephones),explorersanddisaster-reliefteams.Today’smobiletelephonesdependonearth-boundtransmitters,wheretechnicalstandardsvaryfromcountrytocountry.Sobusinesstravelerscannotusetheirmobilephonesoninternationaltrips.Satellitetelephoneswouldmakethatpossible.

MESSAGING.Satellitemassagershavethesameglobalcoverageassatellitetelephones,butcarrytextalone,whichcouldbeusefulforthosewithlaptopcomputers.Equippedwithasmallscreenliketoday’spapers,satellitemassagerswillalsoreceiveshortmessages.

TRACKING.Voiceandmessagingsystemswillalsotelltheiruserswheretheyaretowithinafewhundredmeters.Combinedwiththemessagingservice,thelocationservicecouldhelprescueteamstofindstrandedadventurers,thepolicetofindstolencars,exporterstofollowtheprogressofcargoes,andhaulagecompaniestocheckthatdriversarenotdetouringthepub.America’smilitaryGlobalPositioningSystem(GPS)satellitewillprovidebetterpositioninginformationtoanyonewhohasareceiverfortheirsignals,butGPSdoesnotcarrymessages,sosuchareceivercannotbeusedonitsownfortrackingorrescue.Bythemid-1990s,GPSreceiverswillbeabletotellpeoplewheretheyaretowithin70metersanywhereintheworld,andtowithinameterorsoinareaswheretheserviceissupplementedbyground-basedtransmitter.

16.Globalsatellitecommunicationssystemswillbeusefulto.

A.laptopcomputerusers

B.remotevillages

C.disaster-reliefteams

D.allabove

17.Satellitetelephonewillmake.

A.businesstravelersusemobilephonesoninternationaltrips

B.possiblecallsfromanywhereonearthtoanywhereelse

C.explorershappy

D.allabove

18.Whichofthefollowingistrue?

A.ThepositioningprecisionofthevoicesystemisbetterthanthatofGPS.

B.ThepositioningprecisionofGPSisBetterthanthatofthevoicesystem.

C.ThepositioningprecisionofthemessagingsystemisbetterthanofGPS.

D.Thepositioningprecisionofvoicesystemisbetterthanthatofthemessagingsystem.

19.Whatcanwesayaboutthenewglobalsatellitecommunicationssystems?

A.Theyarewidelyused.

B.Theyareveryhelpful.

C.Theyarecostly.

D.BothAandB.

20.Whichofthefollowingmaybethebesttitleforthepassage?

A.GlobalSatelliteCommunications

B.NewVoiceandMessagingSystem

C.NewGenerationSatellite

D.AlwaysinTouch

Scatteredthroughtheseasoftheworldarebillionsoftonsofsmallplantsandanimalscalledplankton.Mostoftheseplantsandanimalsaretoosmallforthehumaneyetosee.Theydriftaboutlazilywiththecurrents,providingabasicfoodformanylargeranimals.Planktonhasbeendescribedastheequivalentofthegrassesthatgrowonthedrylandcontinents,andthecomparisonisanappropriateone.Inpotentialfoodvaluehowever,planktonfaroutweighsthatofthelandgrasses.Onescientisthasestimatedthatwhilegrassesoftheworldproduceabout49billiontonsofvaluablecarbohydrateseachyear.Thesea’splanktongeneratesmorethantwiceasmuch.

Despiteitsenormousfoodpotential,littleeffortwasmadeuntilrecentlytofarmplanktonaswefarmgrassesonland.Nowmarinescientistshaveatlastbeguntostudythispossibility,especiallyasthesea’sresourcesloomevenmoreimportantasameansoffeedinganexpandingworldpopulation.

Nooneyethasseriouslysuggestedthat“planktonburgers”maysoonbecomepopulararoundtheworld.Asapossiblefarmedsupplementaryfoodsource,however,planktonisgainingconsiderableinterestamongmarinescientists.

Onetypeofplanktonthatseemstohavegreatharvestpossibilitiesisatinyshrimplikecreaturecalledkrill.Growingtotwoorthreeincheslong,krillprovidethemajorfoodforthegiantbluewhale,thelargestanimalevertoinhabittheEarth.Realizingthatthiswhalemaygrow100feetandweigh150tonsatmaturity,itisnotsurprisingthateachonedevoursmorethanonetonofkrilldaily.

Krillswimaboutjustbelowthesurfaceinhugeschoolssometimesmileswide,mainlyinthecoldAntarctic.Becauseoftheirpinkcolor,theyoftenappearasasolidreddishmasswhenviewedfromashiporfromtheair.Krillareveryhighinfoodvalue.Apoundofthesecrustaceanscontainsabout460calories—aboutthesameasshrimporlobster,towhichtheyarerelated.

Ifthekrillcanfeedsuchhugecreaturesaswhales,manyscientistsreason,theymustcertainlybecontendersasnewfoodsourceforhumans.

1.Whichofthefollowingbestportraystheorganizationofthepassage?

A.Theauthorpresentstheadvantagesanddisadvantagesofplanktonasafoodsource.

B.Theauthorquotespublicopiniontosupporttheargumentforfarmingplankton.

C.Theauthorclassifiesthedifferentfoodsourcesaccordingtoamountofcarbohydrate.

D.Theauthormakesageneralstatementaboutplanktonasafoodsourceandthenmovestoaspecificexample.

2.Accordingtothepassage,whyisplanktonregardedtobemorevaluablethanlandgrasses?

A.Itiseasiertocultivate.

B.Itproducesmorecarbohydrates.

C.Itdoesnotrequiresoil.

D.Itismorepalatable.

3.Whydoestheauthormention“planktonburgers”?

A.Todescribetheappearanceofonetypeofplankton.

B.Toillustratehowmuchplanktonawhaleconsumes.

C.Tosuggestplanktonasapossiblefoodsources.

D.Tocomparethefoodvaluesofbeefandplankton.

4.Whatismentionedasoneconspicuousfeatureofkrill?

A.Theyarethesmallestmarineanimals.

B.Theyarepinkincolor.

C.Theyaresimilarinsizetolobsters.

D.Theyhavegrasslikebodies.

5.Theauthormentionsallofthefollowingasreasonswhyplanktoncouldbeconsideredahumanfoodsourceexceptthatitis___.

A.highinfoodvalue.

B.inabundantsupplyintheoceans.

C.anappropriatefoodforotheranimals.

D.freeofchemicalsandpollutants.

We can begin our discussion of “population as global issue” with what most persons mean when they discuss “the population problem”: too many people on earth and a too rapid increase in the number added each year. The facts are not in dispute, It was quite right to employ the analogy that likened demographic growth to “a long, thin powder fuse that burns steadily and haltingly until it finally reaches the charge and explodes.”

To understand the current situation, which is characterized by rapid increases in population, it is necessary to understand the history of population trends. Rapid growth is a comparatively recent phenomenon. Looking back at the 8,000 years of demographic history, we find that populations have been virtually stable or growing very slightly for most of human history. For most of our ancestors, life was hard, often nasty, and very short. There was high fertility in most places, but this was usually balanced by high mortality. For most of human history, it was seldom the case that one in ten persons would live past forty, while infancy and childhood were especially risky periods. Often, societies were in clear danger of extinction because death rates could exceed their birthrates. Thus, the population problem throughout most of history was how to prevent extinction of the human race.

This pattern is important to notice. Not only does it put the current problems of demographic growth into a historical perspective, but it suggests that the cause of rapid increase in population in recent years is not a sudden enthusiasm for more children, but an improvement in the conditions that traditionally have caused high mortality.

Demographic history can be divided into two major periods: a time of long, slow growth which extended from about 8,000 BC.till approximately AD. 1650. In the first period of some 9600 years, the population increased from some 8 million to 500 million in 1650. Between 1650 and the present, the population has increased from 500 million to more than 4 billion. And it is estimated that by the year 2000 there will be 6.2 billion people throughout the world. One way to appreciate this dramatic difference in such abstract numbers is to reduce the time frame to something that is more manageable. Between 8000BC and 1650, an average of only 50,000 persons was being added annually to the world’s population each year. At present, this number is added every six hours. The increase is about 80,000,000 persons annually.

1.Which of the following demographic growth pattern is most suitable for the long thin powder fuse analogy?

A.A virtually stable or slightly decreasing period and then a sudden explosion of population.

B.A slow growth for a long time and then a period of rapid, dramatic increase.

C.Too many people on earth and a few rapid increase in the number added each year.

D.A long period when death rates exceeds birthrates and then a short period with higher fertility and lower mortality.

2.During the first period of demographic history, societies were often in danger of extinction because___.

A.only one in ten persons could live past 40.

B.there was higher mortality than fertility in most places.

C.it was too dangerous to have babies due to the poor conditions.

D.our ancestors had little enthusiasm for more children.

3.Which statement is true about population increase?

A.There might be an increase of 2.2 billion persons from now to the year 2000.

B.About 50,000 babies are born every six hours at present.

C.Between 8000 BC and the present, the population increase is about 80,000,000 persons each year.

D.The population increased faster between 8000BC and 1650 than between 1650 and the present.

4.The author of the passage intends to___.

A.warn people against the population explosion in the near future.

B.compare the demographic growth pattern in the past with that after 1650.

C.find out the cause for rapid increase in population in recent years.

D.present us a clear and complete picture of the demographic growth.

5.The word “demographic” in the first paragraph means___.

A.statistics of human.

B.surroundings study.

C.accumulation of human.

D.development of human.