GWD 17-38

maseryou

 

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

请问D的时态该怎么解释啊，前面讨论的贴子也没解释清楚

insonbia83

下面一段话对D的时态或许有点帮助

这段话是从专业的英文文章下载,

Neanderthals were thought to have died out as modern humans arrived in Europe

当现代人到达欧洲时N已经灭绝了,通常情况会用had died

weixiaozi09

 who　is thought说明了是现在最认为。。。