一道想不懂的题目，难难难～～

All Y chromosomes in existence today are descended from a single ancestor’s who is thought to have lived about 140,000 years ago.

A.      a single ancestor’s who is thought to have lived

B.       a single ancestor’s who was thought to live

C.      a single ancestor whom it is thought had lived

D.      the Y chromosome of a single ancestor who is thought to have lived

E.       the Y chromosome of a single ancestor whom it was thought had lived

我选Ａ，答案是Ｄ，我觉得ＴＨＥ　Ｙ　ＣＨＲＯＭＯＳＯＭＥ　ＯＦ．．．好象没有ＡＮＣＥＲＳＴＯＲ＇Ｓ　简洁．我不知道所有格什么时候可以直接加＇Ｓ，什么时候要ＯＦ．．结构．请指教～～～～ＰＬＥＡＳＥ

我觉得是因为who是修饰人，而A选项who修饰了ancestor's 。 of结构用于没有生命的物体，  's用于人

拙见，还是等大牛说吧

A of B 的结构比较好。比较明确

A's 的省略结构不能用

who is thought to have lived修饰的是ancestor

选A的话 ancestor’s 后面接who，那么变成了修饰 Y chromosome

不要忽略了's的所有格，而误以为指代没问题