so as to的用法

allygmat7

我感觉so as to 好像有主动的因素存在。SB DO STH SO AS TO BALALA。。但是下面这题Often major economic shifts are so gradual as to be indistinguishable at first from ordinary fluctuations in the financial markets.

A.so gradual as to be indistinguishable

B.so gradual so that they can be indistinguishable

C.so gradual that they are unable to be distinguished

D.gradual enough not to be distinguishable(A)

E.gradual enough so that one cannot distinguish them
答案却是选A。假如C是 SO GRADUAL THAT THEY ARE indistinguishable 的话，应该怎么选呢？
跪求各位大虾赐教

allygmat7

再补充 ：OG10-171. In 1527 King Henry VIII sought to have his marriage to Queen Catherine annulled so as to marry Anne Boleyn.
(A)    so as to marry
(B)    and so could be married to
(C)    to be married to
(D)    so that he could marry
(E)    in order that he would marry
Key: D
这题怎么又会选D呢

IMARCUS

第二题的so as to 是以至于的意思，后面缺少主语he也就是king henry ，所以用he 代替。

allygmat7

楼上说的。好像跟我问的不大对应- -。。不是很懂

Nickyl90

帮顶出来，同问这个知识点