the same sth as 和the same as sth有什么区别？

[A] be the same as [B] 是最常见的用法，这道题中也是这样，只不过在 the same 和 as 中间加了一个副词 today。

[A] [verb] the same [sth.] as [B] [verb] 是另一种表达方式。
如果 A is the same as B 翻译成中文是“A 和 B 是相同的”，那 A is the same [sth.] as B is 翻译后就是“A 是和 B 相同的[事物]”。其他例句：

I do the same thing as he did.
You are in the same situation as mine.
(= You are in the same situation as my situation.)
= You are in the same situation as I am.
= You are in the same situation that I am in.
= Your situation is the same as mine.

从这道题的做题思路上来说，用排除法比较好：

如果选 A，它的句式是类似于下面的用法：

His bag is the same as my bag.
His bag is the same as mine.

这种情况下，需要 be the same as 的前后项所指代的是同类事物，这样才能说 XXX 和 YYY 是一样的。

而题目中 are the same as 前面是「电话的运作原理」，后面就变成了 today they were in the nineteenth century，这后一项从语法上是说不通的（既有 today，又同时说 in the nineteenth century），因此要排除 A 项。

如果选 B，下划线后面的 they were in the nineteenth century 就成了多余的部分，只有把它去掉 或者像 C 项 一样加上 as，句子才能说得通。因此排除 B 项。

如果选 D，句子结构看起来就更混乱了，需要进行调整才说得通，即变成：

The operating principles of the telephone today are the same as what they were in the nineteenth century.

因此排除 D 项。

最后来看 C，句子结构如下：

The operating principles of the telephone are the same today as they were in the nineteenth century.

其中 today 的作用其实是修饰主语「电话的运作原理」，它的位置也可以移到前面去，读起来更顺口一些：

The operating principles of the telephone today are the same as they were in the nineteenth century.

句子的意思都是将「如今的电话的运作原理」与「十九世纪的电话的运作原理」做比较。

这里的 today 在选项里是具有一定迷惑性的， 因为它其实并不是用来和 the same as 搭配的，而是仅用来修饰句子的主语。