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 the concept of an age in which great ice sheets had existed in now currently temperate areas.
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 the concept of an age in which great ice sheets had existed in now currently temperate areas.
(A) in which great ice sheets had existed in now 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
(E) when great ice sheets existed in areas now that are temperate
曼哈顿语法里关于Past Perfect,我把它分成三点记,如果用过去完成时,需要a和b两个条件需要同时满足。
a. you should use Past Perfect only to clarify or emphasize a sequence of past events;
b. the earlier event should somehow have a bearing on the context of the later event;
c. If the sequence is already obvious, we often do not need Past Perfect.
另外,以下这段是在DUKB24的千行EXCEL里面看到的,我抄在笔记本上了,应该是国外论坛的instructor写的,希望可以帮到楼主。也是用过去完成时的条件:
1) for past actions that were ongoing until, or relavant to, a later past action
OR
2) for past actions that were ongoing until, or relavant to, a later past time marker
另外第二句far outside the range of present-day glaciers,我觉得是说明了他研究提出的观点是1837年就已经结束了,但是因为”这题中的表过去的动词是led,in 1837也可以看成是一个过去的time marker,但exist这个动词和led以及1837年都没有关系“所以还是用过去完成时。
另外谢谢LS分享的过去完成时使用条件哈