再问SO....AS TO的问题：SEC 2-14

.       Although one link in the chain was demonstrated to be weak, but not sufficiently so to require the recall of the automobile.

(A) demonstrated to be weak, but not sufficiently so to require

(B) demonstrated as weak, but it was not sufficiently so that it required

(C) demonstrably weak, but not sufficiently so to require

(D) demonstrably weak, it was not so weak as to require（D）

(E) demonstrably weak, it was not weak enough that it required

Choice E is less concise and idiomatic than D; moreover, it is imprecise to say that one link in the chain (the referent of it) actually required the recall. The question is of middle difficulty.

我记得以前一个帖子说用so..as to的时候，as to后面的动作必须和主句一致。在这个题里，毫无疑问就应该是chain。然而OG的解释说：it is imprecise to say that one link in the chain (the referent of it) actually required the recall.

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这是怎么回事呢？

so..as to表目的。而E的错误是it is imprecise to say that one link in the chain (the referent of it) actually required the recall。