（1）     GWD-17-Q38

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

1. a single ancestor’s who is thought to have lived
2. a single ancestor’s who was thought to live
3. a single ancestor whom it is thought had lived
4. the Y chromosome of a single ancestor who is thought to have lived
5. the Y chromosome of a single ancestor whom it was thought had lived

  不明白为什么是d

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

who is wrong

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

who is wrong ."was" is wrong

C:a single ancestor whom it is thought had lived
    

whom不对

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

whom不对，was不对

有生命的所有格不是应该用 's表示吗？

D E 中 用的是of 结构，这样可以吗？

只是说无生命的东西最好用sth. of sth 并没有说有生命的东西不能有of.况且这个地方用了of sth.后 后面的定从刚好可以很好地修饰sth.

我同意前半段，但是有疑问为何此处要用have lived?