注意:此页面搜索的是所有试题
Thereasonsforthechangesarecomplex.Itisclearthatpollutionoftheairandwaterbyfactoriesisaffectingtheenvironment.Treesandothervegetationdie,andsosoiliseroded.themoretreesthatdie,thelesswaterisheldintheearth.theneedforwoodforfuelandbuildingsleadstofurtherdeforestation,whichcausesfurthersoilerosion.Localfarmersfinditmoreandmoredifficulttomakealiving.theyendupusinginefficientfarmingmethods,whichagainleadstosoilerosion.

参考答案