[求助]og 59

lr2007gr

In OG 11th

59. His studies of ice-polished rocks in his Alpine homeland, far outside the range of present-day glaciers, led Louis Agassiz in 1837 to propose* concept of an age in which great ice sheets' had existed in now currently temperate areas.

A) in which great ice sheets had existed: currently temperate areas

(B) in which great ice sheets existed in what are now temperate areas

(C) when great ice sheets existed where there were areas now temperate

(D) when great ice sheets had existed in current temperate areas                    （B）

(E) when great ice sheets existed in areas now that are temperate

Why does it use past tense "existed", not past perfect "had existed"?

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super_pig

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以下是引用sunyi001在2006-3-17 21:55:00的发言：
This verb form is used with had to show the order of two events that took place in the past. OG 11th page 632

By the time L proposed xxx  I think the ice sheet had already disapeared.

So the past perfect verb form shows the order of two events took place in the past.

cocomalawi

这是过去时态和过去完成的区别.

. His studies of ice-polished rocks in his Alpine homeland, far outside the range of present-day glaciers, led Louis Agassiz in 1837 to propose* concept of an age in which great ice sheets' had existed in now currently temperate areas.

很明显,句子的主语是his studies,谓语是led  (to),

谓语动词用的是一般过去时态

我们在使用过去完成时态一般指的是过去的过去,就与定语从句所修饰的age想矛盾拉

rheazhang

以下是引用cocomalawi在2006-3-20 22:49:00的发言：

这是过去时态和过去完成的区别.

. His studies of ice-polished rocks in his Alpine homeland, far outside the range of present-day glaciers, led Louis Agassiz in 1837 to propose* concept of an age in which great ice sheets' had existed in now currently temperate areas.

很明显,句子的主语是his studies,谓语是led  (to),

谓语动词用的是一般过去时态

我们在使用过去完成时态一般指的是过去的过去,就与定语从句所修饰的age想矛盾拉

黄色部分不太明白啊

sausau

今天也遇到这道题，同样的困惑。看了楼上的解释后还是困惑。

stoopy

同问，还想听听更多的解释！

ainiAnnie

过去完成时 是 不可以 和 now currently 这些词一起出现的吧。。。。
个人意见，仅供参考。