作者：英吉
In a review of 2,000 studies of human behavior that date back to the 1940s, two Swiss psychologists,declaring that since most of the studies had failed to control for such variables as social class and family size, none could be taken seriously.
(A) psychologists, declaring that since most of the studies had failed to control for such variables as social class and family size,
(B）psychologists, declaring that most of the studies failed in not controlling for such variables like social class and family size, and
(C) psychologists declared that since most of the studies, having failed to control for such variables as social class and family size,
(D)psychologists declared that since most of the studies fail in controlling for such variables like social class and family size,
(E)psychologists declared that since most of the studies had failed to control for variables such as social class and family size,
题目分析：A和B都用declaring，没有谓语，干掉。CDE三个选项之间最大的差距就是fail这个词的词性，一个用进行时态，可是语意决定这个不是正在进行的事情，不能用having，D用过去时fail而E用过去完成时had faild，根据意思我们可以判断出fail to control这个事情是原因，应该先发生，而none could be taken是结果，应该后发生，而could be taken是划线外，是一定对的，所以为了保证原因在could这个动作发生之前出现，必须用过去完成时，选E。
