前面一句古诗后面一句英语 这句英语，前半句是什么语法结构

As a child she lives with someone she doesn't know is her aunt, who treats her very badly.

someone后的确省略了who或that。这是关系代词在定语从句中作主语可以省略的情形之一。稍微详细一点的语法书都会提到这个知识点。本句中因为有了主谓结构（she said, she believed等）的插入语she doesn't know，所以who或that可以省，也可以不省。举例说明一下：

省了的：Mr. Malatras said that the city was already meeting the state’s testing metric of roughly 8,300 a day, a threshold he said was based on federal guidance. threshold后省略that或which。

The rise of the service sector, Mr Suzman suggests, is a way for people to keep themselves busy, even though many individuals are dissatisfied with work they feel is meaningless. work后省略that或which。

没省的：

Before becoming president Mr Trump spent much of his money on golf courses, hotels and other trophy assets that the Times says have since racked up huge tax losses.

题主问题中的前半句含有一个较为高级的定语从句，或者说关系从句，因为英文中称这类从句为relative clause。

如果两句话在某些元素上有重合的地方，一般都可以把其中一句改写为关系从句，比如：

1. Lisa has an aunt.

2. The aunt treats her very badly.

假如上面两句话中的aunt是同一个人，那么我们就可以把其中一句改为关系从句。

改写的方法也很简单，比如我们现在要把第2句改为关系从句，先找到重合元素the aunt, 因为the aunt在句2中作主语，所以我们把它改为关系代词who，句2变成了：

3. who treats her very badly.

现在把改写后的关系从句加到句1的重合元素（an aunt）后面就好了：

4. Lisa has an aunt who treats her very badly.

现在我们来分析一下题主问题中的前半句：

5. (As a child) she lives with someone she doesn't know is her aunt.

As a child 作为状语，是一个修饰语，我们先把它删掉，句子变成：

6. She lives with someone she doesn't know is her aunt.

可以把句6看成是由下面这两句话改写而成：

7. She lives with someone.

8. She doesn't know that person is her aunt.

句7中的someone和句8中的that person重合，因此在改写时，把句8中的重合元素that person改为关系代词who，因为that person做she doesn't know后面的宾语从句的主语，改写后变成：

9. She doesn't know who is her aunt.

下一步再把who提到句首作为从句的引导词，变成：

10. who she doesn't know is her aunt.

接下来再把句10加到句7的重合元素someone后面，变成：

11. She lives with someone whoshe doesn't know is her aunt.

确实会有人用句11这种写法，大部分Native speakers也能接受，但是这种句子最正式的写法，是把who删掉，变成句6也就是题主问题中的句子那样：

She lives with someone she doesn't know is her aunt.

为什么会删掉who？

可能是因为受到紧随其后的she doesn't know的影响，当who出现在she doesn't know前面时，它更像是know的宾语，而我们知道当关系代词做从句的宾语时是可以省略的。

当关系代词做关系从句的宾语从句的主语时可以省略！