prep-1-64 （when placed是介词结构？？）

64.       (27947-!-item-!-188;#058&003452)

Recently documented examples of neurogenesis, the production of new brain cells, include the brain growing in mice when placed in a stimulating environment or neurons increasing in canaries that learn new songs.

(A) the brain growing in mice when placed in a stimulating environment or neurons increasing in canaries that

(B) mice whose brains grow when they are placed in a stimulating environment or canaries whose neurons increase when they

(C) mice's brains that grow when they are placed in a stimulating environment or canaries' neurons that increase when they

(D) the brain growth in mice when placed in a stimulating environment or the increase in canaries' neurons when they

(E) brain growth in mice that are placed in a stimulating environment or an increase in neurons in canaries that

答案是Ｅ没什么问题　就是对于ＰＲＥＰ笔记中的一句话不理解

介词+动词分词在句首,逻辑主语等于主句的主语;在句尾,逻辑主语可能等于主句的主语,也可能等于所修饰的动词的逻辑主语

(A) the brain…无法与the production of…平行；growing使用错误,应该用grow的名词形式growth来替换,increasing应该用increase替换;介词结构when placed无论是修饰主句的主语还是所修饰动词(include)的逻辑主语,该结构都是修饰的documented examples,而从逻辑意思上看,when placed应该修饰mice,因此when placed修饰对象错误.

请各位指教　这为什么是介词结构呢？？？谢谢！！！ 

(A) the brain…无法与the production of…平行；growing使用错误,应该用grow的名词形式growth来替换,increasing应该用increase替换;介词结构when placed无论是修饰主句的主语还是所修饰动词(include)的逻辑主语,该结构都是修饰的documented examples,而从逻辑意思上看,when placed应该修饰mice,因此when placed修饰对象错误.

请各位指教　这为什么是介词结构呢？？？谢谢！！！ 

我也感觉这里不应该是介词结构吧,要不是when做代词引导宾语从句,要不when做副词引导状语从句,不知道说的对不对,我还想问个问题,介词+动词分词在句首,逻辑主语等于主句的主语;在句尾,逻辑主语可能等于主句的主语,也可能等于所修饰的动词的逻辑主语这个规律我怎么原来没见过,是可以用在考场上的么??NN们来帮解答一下吧~