gwd 17 38

laurawang2234

38. GWD17-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.



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

答案d 我选c c是有问题thought后面应该加个that是吗？谁能给解释下“the y chromosome
of a single ancestor”是个什么结构么？

min356478

the y chromosome  of a single ancestor 是 A of B结构

这两道题很像呢~


1.According to scientists at the University of California, the pattern of changes that have occurred in human DNA over the millennia indicate the possibility that everyone alive today might be descended froma single female ancestor who lived in Africa sometime between 140,000 and 280,000 years ago.
(A) indicate the possibility that everyone alive today might be descended from a single female ancestor who
(B) indicate that everyone alive today might possibly be a descendant of a single female ancestor who had
(C) may indicate that everyone alive today has descended from a single female ancestor who had
(D) indicates that everyone alive today may be a descendant of a single female ancestor who（D）
(E) indicates that everyone alive today might be a descendant from a single female ancestor who

前后（粉色底的）是并列关系，所以排除C，

be thought to be是固定用法吧，***被认为***

小月潇湘

C的whom，不应该用宾格。然后是错在时态，这里不能用过去完成，因为没有一个对应的过去时提示。应该用现在完成，因为主句用了一般现在，后面用现在完成表示对现在的影响。

个人浅见。

xiaoaojiang

D.the Y chromosome of a single ancestor who is thought to have lived
A.a single ancestor’s who is thought to have lived
A和D的区别就在前半段吧？我想问问说all C 都是从一个祖先的C传下来的，我们怎么判断这个说的是the Y chromosome of a single ancestor 而不是the Y chromosomes of a single ancestor 呢？为了让这个染色体也有复数的可能我选了A。。。。

tania_zhang

我明白了，这个a single ancestor's who。。。这里的who的先行词是一个所有格形式，也就是指的是染色体，显然不是染色体住在。。

我的理解对吗

laurawang2234

看着看着觉得d是正确的

acrophobia

have lived怎么可以和ago搭配呢？

stucashS

其实我的疑问是为什么这里用who is thought to have lived ，为什么是完成时呢？

seanceserene

我怎么觉得问题出在whom上面呢。。。。

nymphl

是呀是呀，明明是ago为什么为什么是have lived...?