[問題]大全-14-13

[best555tw]

13. 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

答案B
為什麼不能用when?
D為什麼不對呢?????

[Pufa]

when可以用。
D的問題出在修飾age的片語裡用了had existed，
這裡只要用過去式描述一下有關這個age的事實就可以了。