这句话为什么又有ed又有ing.Althoughitisusefultoartificiallyisolatethesesubjectsforthesakeofdiscussion,inrealitytheyareinterconnectedandcanbeemployed(为什么是ed?)sparingly,inselected(为什么是ed)combinationsor

　　这句话为什么又有ed又有ing.

　　Althoughitisusefultoartificiallyisolatethesesubjectsforthesakeofdiscussion,inrealitytheyareinterconnectedandcanbeemployed(为什么是ed?)sparingly,inselected(为什么是ed)combinationsorsometimes,alltogether.Itisimportanttorememberthatitisn'tnecessarytoemploy(为什么又是动词原形)allofthesemethods,allofthetime.Onthecontrary,constraintandselectivityinemploying(为什么又是ing,而且没有是动词)thesetechniqueswilldeterminetheidentityofyourworkandwillaffordyouraudiencethemetalspacetoengagewithitwhole-heartedly.