发出keep动作的是个人而不是 chalice，所以 状语to keep it from对应的主语是人。正常句子是sb. bury chalice to keep it from .....

in order to/ to 没有区别
it在这需要，表示防止什么被偷

如果不加it ,就不知道要防止什么被偷。C也是错在没有it

被动变成主动再读，sb bury xxx to keep it from being stolen. 还原后发现it不能省略。

实义成分缺失
第一步 看是否冗余。防止被偷 与 防止圣杯被偷，圣杯不冗余
第二部 缺失表任意。 ACE 防止任意一个东西被偷。 句意无法和前半段形成联系。圣杯被埋起来 肯定是防止圣杯被偷，所以it不可以省略 选C

**The phrase to keep from being stolen is incomplete and does not indicate what might be stolen. Inserting a pronoun makes it clear that it is the chalice that might be stolen.
**keep oneself/sb from sth/doing sth // The church bells keep me from sleeping.//
**keep（oneself）from doing sth // She could hardly keep (herself) from laughing.//

B选项："to keep from being stolen" does not indicate what might be stolen, so a pronoun is needed between keep and from.
C选项：to avoid it from being stolen

避免什么被偷 要加个代词 否则不知道是什么！！！！

A选项：缺代词
B选项："to keep from being stolen" does not indicate what might be stolen, so a pronoun is needed between keep and from.
C选项：to avoid it from being stolen
D选项：这样表达wordy
E选项：keep it from,

看到后面by invaders确定主语，不用avoid（自身）

to keep it from表示to keep意图的发出者不是chalice，而是烧它的人，to keep from没明确to keep意图的发出者是chalice（需要用to keep itself from表示动作的承受者是自身）还是其他

the planning commission voted to extend the highway 10 miles farther south, to allow commuters from the southern suburbs to travel downtown more quickly
--> this is an active construction. the modifier implies that "to allow..." was actually the intention of the planning commission; if that's not the case, this sentence is not ok.

if "to + verb" correctly expresses the intention of the ACTION then the sentence is fine.
the highway was extended 10 miles farther south, to allow commuters from the southern suburbs to travel downtown more quickly
--> this is a passive construction. "to allow..." is clearly not the intention of the highway itself -- in context, it's the intention of whoever planned the highway extension -- but, in a passive construction, this kind of usage is ok.

这里加it更好，消除了歧义，说明不能单单用多代词就排除选项

先排除D：in order to do 不用that，另起一句话不好

ACE：目的状语to keep的主语是chalice，而文物不能有保护自己的主观目的，不能自己做to keep的动作

B:虽然it略微有歧义，可指代chalice/Ireland
如果chalice是to do目的的主语--自己对自己做一件事 要用itself，而不是it，所以keep it from消除了歧义
加了it，说明to keep的动作发生者不是chalice，是谁这里没说，反正不是chalice
所以比ACE好

其实：单看ACE 几乎没有差别，所以只能3个都错

这里加it更好，说明不能单单用多代词就排除选项！

but also 没搭配的not only ---排除DE
主语应该是scientists an historians，不是an attempt---排除CE

AB的区别
A:scientists an historians,插入语in their attempt，are hoping
谓语是hope---主要动作 状语---在他们的尝试里 不合逻辑；且attempt，明显做动词，而不是这里的名词

B：scientists an historians are attempting to do， hoping
谓语：尝试 伴随状语：希望 符合逻辑

越做越晕，两次都错选A。连最简单的搭配都还给初中语文老师了。
[keep someone/something from doing something] to prevent someone from doing something or prevent something from happening

C选项avoid 后面需加it表示"避免chalice being stolen"，如果不加it则没表达清楚avoid 什么被偷。

B和C，C 没有表明是避免谁被偷