单选题According to some theorie

问题补充：

单选题Accordingtosometheories________frompsychoanalysis,lifeissupposedlyeasier;andmorepleasantwhenanxietyisovercome.A.obtainB.obtainingC.to obtainD.obtained

答案：

D解析本题考查的是非谓语动词，由于逻辑主语theories与动词obtain是被动关系，故选择表示被动含义的D（-ed分词）