定语从句缺主语怎么看
定语从句缺主语怎么看，一起来学习吧。
在从句里看的,如
He is the person who is my teacher. (这里用who ,是因为后面出来的是动词,动词前事缺主语的,因此用主格的who)
He is the person (whom) i usually turn to for help.(这里是缺定语从句的turn to 的`宾语,因此用宾格）
附：如何看定语从句中缺什么成分
在学习定语从句时，分析从句中的成分是非常重要的。关系代词that ,which ,who 和whom在定语从句作主语，宾语或表语，也就是说，如果在定语从句中，缺少这些成分的话，就用这些词。关系代词whose在定语从句中做定语。关系副词where ,whenh和why在定语从句中充当状语。我们知道，定语从句的结构是（先行词）+关系词+定语从句。关系词的选择主要看定语从句中缺少了什么成分。
如:This is the factory ______his father worked ten years ago.在his father worked ten years ago部分，work是一个不及物动词，明显缺少了地点状语，只能用关系副词where。
再如：The boy _____ name is Tom didn't come to school yesterday.在_____ name is Tom中，缺少了name的定语，所以用关系代词whose。又如：This is the man ______took my pen yesterday. 在______took my pen yesterday中，明显缺少了主语，所以用who或that.
附：定语从句详解
as, which 非限定性定语从句
由as, which 引导的非限定性定语从句，as和which可代整个主句，相当于and this或and that.As一般放在句首，which在句中。
As we know, smoking is harmful to ones health.
The sun heats the earth, which is very important to us.
典型例题
1）Alice received an invitation from her boss, ___came as a surprise.
A. it B. that C. which D. he
答案C. 此为非限定性从句，不能用 that修饰，而用which.，it 和he 都使后句成为句子，两个独立的句子不能单以逗号连接。况且选he句意不通。
2）The weather turned out to be very good, ___ was more than we could expect.
A. what B. which C. that D. it
答案B.which可代替句子，用于非限定性定语从句，而what不可。That 不能用于非限定性定语从句，it不为连词，使由逗号连接的两个句子并在一起在英语语法上行不通。
3）It rained hard yesterday, ____ prevented me from going to the park
A. that B. which C. as D. it
答案B.
as 和which在引导非限制性定语从句时，这两个关系代词都指主句所表达的整个意思，且在定语从句中都可以作主语和宾语。
