知识贝壳
知识贝壳
所属栏目：建筑施工英语
Assoonasearlypeoplesestablishedsettlementtheyhadtheproblemofgettingridofsewage——theirorganicwastesand,sometimes,thoseofdomesticanimals.Naturedisposesofsurplusorganicmaterialinfourprincipalwaysbydilution,oxidation,putrefaction,andfiltration.Earlypeoplesrel ......（本文共 5829 字 ） [阅读本文] >>