55. A recent study has found that within the past few years, many doctors had elected early retirement rather than face the threats of lawsuits and the rising costs of malpractice insurance.
(A)  had elected early retirement rather than face
(B)  had elected early retirement instead of facing
(C)  have elected retiring early instead of facing
(D)  have elected to retire early rather than facing
(E)   have elected to retire early rather than face
 
1． 时态：（一级排除A,B,C）
within the past years 做状语表示从过去持续到现在的动作，主句的时态要用完成时。 已经完成的动作用完成时态不能还继续表示进行时态的意思。注意和现在完成进行时态区分。 主要从逻辑意思进行区别：已经选择一个东东, 不是已经选择一个动作
C is faulty because have elected, which is correct in tense, cannot idiomatically be followed by a
participle such as retiring .this is very important. It means we cannot both finish sth and at the same time, identify this same sth as ongoing….
 
1.       平行结构：（二级排除D）
名词/ 动词 / 分词 不能并列

2.       优先结构：
rather than > instead of