Itisonlyduringthelastfewyearsthatmanhasgenerallyrealizedthatintheworldofnatureabalanceexistsbetweenallformsoflife.Nolivingthingcanexistbyitself.Itispartofasysteminwhichallformsoflifearejoinedtogeth

　　Itisonlyduringthelastfewyearsthatmanhasgenerallyrealizedthatintheworldofnatureabalanceexistsbetweenallformsoflife.Nolivingthingcanexistbyitself.Itispartofasysteminwhichallformsoflifearejoinedtogether.Ifwechangeonepartofthenatureorder,thiswillalmostcertainlybringaboutchangesinsomeotherparts.

　　Thecuttingofforestsreducedthesupplyofoxygen.Thekillingofweedsandinsectsbychemicalsledtothewide-spreadpoisoningofanimalsandbirds.Thethrowingofwasteproductsintotheoceanhurtlifeinthesea,whilewastegaseschangedthechemicalbalanceoftheatmosphereandshutoutsomeofthesun’snecessarylife-givingrays.

　　Andsowecouldgoonaddingmoreexamplesuntilindespair(绝望)wemightfeellikegivingupthestruggletocontroltheseharmfulhumanactivities.Manisverycleveratchangingtheworldaroundhimtosatisfyhisimmediateneeds,butheisnotsocleveratlookingfarahead,oratthinkingaboutwhatthefutureresultsofhisactionmightbe.Manmaywelldestroyhimselfbecauseofhissillyaction.

　　小题1:Thefirstparagraphtellsusthat_____.A．alllivingthingsinnaturedependoneachotherB．everythinginnaturecan’texistwithoutthehelpofmanC．manhasknowntheimportanceofthebalanceofnatureforalongtimeD．nolivingthingcanlivenaturally小题2:Inthesecondparagraphtheexamplesgivenareusedtoprovethat_____.A．allformsoflifebelongtoasysteminwhichallthepartscanbechangedforoneanotherB．itisonlyduringthelastfewyearsthatmanhasgenerallyknownthebalanceofnatureC．therearesomelivingthingswhichcanexistbythemselveswithoutchangeD．wecan’tchangeoneformoflifewithoutdestroyingthebalanceofnature小题3:Thelastparagraphsuggeststhatinordertogethisimmediatebenefits(利益)_____.A．manisalwaysanxioustocontrolhisactivitieswithinlimitsB．manisalwaystooeagerinplanningfordistantfutureC．manoftenfailstothinkabouttheirfutureresultsofhisaction