Inthedecade（十年）ofthe1970stheUnitedNationsorganizedseveralimportantmeetingsonthehumanenvironmenttostudyaveryseriousproblem．Wehumansaredestroyingtheworldaroundus．Wemustlearntoprotectthemorlifewillbeverybadforourchildrenandgrandchildren．

Thereareseveralmajoraspectstothisproblem．

Population

Mostproblemsoftheenvironmentcomefrompopulationgrowth．In1700therewere635millionpeopleintheworld;in1900therewere1．6billion;in19502．5billion;andin19804．4billion．Intheyear2010therewillbe7．3billion．Morepeopleneedmorewatermorefoodmorewoodandmorepetroleum．

Distribution

Scientistssaythereisenoughwaterintheworldforeveryonebutsomecountrieshavealotofwaterandsomehaveonlyalittle．Someareasgetallrainduringoneseason．Therestoftheyearisdry．

Petroleum

Weareusinguptheworld’spetroleum．Weuseitinourcarsandtoheatourbuildingsinwinter．Farmersusepetrochemicalstomakethesoilrich．Theyusethemtokillinsectsonthoseplants．Thesechemicalsgointoriversandlakesandkillthefishthere．Thousandsofpeoplealsodiefromthesechemicalseveryyear．Chemicalsalsogointotheairandpolluteit．Windscarrythispollutedairtoothercountriesandothercountries．

Poverty

Poorfarmersusethesamelandoverandover．Thelandneedsarestsoitwillbebetternextyear．Howeverthefarmermusthavefoodeveryyear．Poorpeoplecutdowntreesforfirewood．Insomeareaswhenthetreesaregonethelandbecomesdesert．Howeverpeopleneedwoodtocooktheirfoodnow．Poorpeoplecannotsavetheenvironmentforthefuture．

Wenowhavetheinformationandtheabilitytosolvethesehugeproblems．Howeverthisisnotaproblemforonecountryoroneareaoftheworld．Itisaproblemforallhumans．Thepeopleandthenationoftheworldmustworktogethertoprotecttheworld’sresources．Noonecontrolsthefuturebutweallhelpmakeit．

Accordingtothepassageourworldisbeingdestroyedmainlybecause______．

A．pollutionisgettingworseandworse

B．populationareincreasinggreatly

C．wehumansareusingupallofournaturalresources

D．distributionisnotreasonable．