知識(shí)貝殼
知識(shí)貝殼
所屬欄目：建筑施工英語(yǔ)
Assoonasearlypeoplesestablishedsettlementtheyhadtheproblemofgettingridofsewage——theirorganicwastesand,sometimes,thoseofdomesticanimals.Naturedisposesofsurplusorganicmaterialinfourprincipalwaysbydilution,oxidation,putrefaction,andfiltration.Earlypeoplesrel ......（本文共 5829 字 ） [閱讀本文] >>