E 倒装错误，应该完全倒装，so 放最前。
BCD 没有连词，语法错

Installed and operated so secretly in the Kennedy Oval was a recording system that
(E)试图用倒装结构来表达，但是此处倒装结构有问题，应该是：so secretly installed and operated in the Kennedy Oval was a recording system that（完全倒装），
因为秘密地是修饰安装的，而不是in哪里

E：by switching around the word order in E, you break the "so X that Y" construction, and "that" now becomes a modifier of "recording system". as such, the subordinate clause introduced by "that" should not have a subject, which it does..

so that。
E 需要完全倒装 so secretly installed and operated was a

Installed and operated so secretly in the Kennedy Oval was a recording system that even Theodore C. Sorensen, the White House counsel, did not know it existed.❌❌
需要完全倒装： so secretly installed and operated in the kennedy oval was a recording system that even......

E没有完全倒装

BD缺少so that句式
A选项：✅
C选项：so that位置❌
E选项：倒装错误 正确的倒装为：so secretly installed and operated in the Kennedy Oval was a recording system that......

E应该是so secretly Installed and operated in the Kennedy Oval was a recording system that……
so secretly副词/修饰状语倒装，起强调作用。

倒装：
if句倒装：助动词/be动词+主语+谓语动词原型=if sb do sth

否定副词前移：否定副词+助动词/be动词+主语+谓语动词原型，如：
Seldom do I go to work by bus.

地点、范围介词短语前置：地点、范围介词短语+谓语动词+主语，如：
Among the surest indications of sunspot cycles is the rate at which trees grow.

than等引导的被比较部分引导的句子某一成分过长，或复合句里某一成分过长，而将另一成分前置以便于理解，引起的倒装。

E没有完全倒装

a選項難道沒有歧異的問題嗎?
that 後面的it 可能指office 也可能指 recording system
雖然透過語意是可以知道 但這樣寫難道不會讓人有歧異的嫌疑嗎?

E中完全倒装才可以，但是这个倒装是错误的。在句子中副词未必不是重读词，即A中也是强调了秘密性

5E正确语序如下：
So secretly installed and operated in the Kennedy Oval Office was a recording system that

1/倒装结构；2/连词

这里不需要区分名词形式和从句的区别吗，安装（install）运行（operate）都是有时间终止点的呀，这个事情已经在历史上结束了？

请问老师可以简单介绍一下排除E选项的“完全倒装”吗？