so that, 如此，以至于，包含一层因果的逻辑关系
enough to do，足够……而能够，没有因果的意思
so prevalent that it was said a squirrel could jump ，it作形式主语，事实主语时said后面的句子，某件事被传说，而不是a squirrel was said，某个人/某样东西被传说

adjective] ENOUGH to..." means, basically, "sufficient to meet a threshold/minimum requirement".
"SO [adjective] that...", on the other hand, is used to emphasize that something is EXTREME.
again, just make up examples in your head -- this time using "so big..." or "so tall..." or "so old..."
if your examples make sense, then, ALL of them will emphasize the EXTREME quality of whatever you are talking about.

A．正确，that后面是结果，it was said是固定搭配，it 是形式主语 that 可以省略
B．a squirrel was said 被动表达不够简单
C．so …to be固定搭配错，而且so …for… to be said表达不简洁
D．没有enough that这个短语
E．enough to do 表示目的，跟so that不一样，改变了逻辑语义

for a squirrel to be said和a squirrel was said that ...都不对，排除BCE。say不能带双宾语。
D: 没有enough that...，排除
剩下A
-----------------------------------------
adjective] ENOUGH to..." means, basically, "sufficient to meet a threshold/minimum requirement".
"SO [adjective] that...", on the other hand, is used to emphasize that something is EXTREME.

只有so/such…that没有enough that

只能it was said 不能是squirrel is said

Chestnut栗子 it was said(that)据说 Bron-on

adjective] ENOUGH to..." means, basically, "sufficient to meet a threshold/minimum requirement".
just think about typical examples of being "tall enough" or "old enough" or "good enough" for various things. these are NOT examples of "extremes"; they're just examples of "things that meet minimum requirements".

it was said that 的that可以省略，特别是对于此句，前面已经出现了that，xxx was so prevalent THAT it was said THAT 这样会显得awfully ugly

if you have
it was ADJ ...
or
it has been/was/is said/believed...

then the "it" doesn't have to stand for anything. you should just memorize this as an idiomatic construction.

"it was a terrible mistake", though, would be incorrect unless "it" actually stood for some noun.

请教老师B错在哪里？

A选项中的it is said 后面的that可以省略吗 之前是觉得that不能省略 所以直接排除了A

想请教下老师ABE的比较，B和A比是因为核心词不同么？A这样的形式主语的句子，核心词是怎么考虑的，真实的主语是看做从属句子还是可以直接理解为主语呢？E是因为啰嗦所以错了么？如果是enough句型，改成enough for a squirrel to jump ...是否正确了呢？谢谢！