像句子My dad's got a camera that takes photos unger water.先行词 a camera是单数,从句that takes photos unger water的谓语动词就用takes
再如：The boys who are from America like China.这里主句是The boys like China.定语从句who are from America 修饰先行词the boys.因为the boys 是复数,所以定语从句who are from America 的谓语动词用复数are
如果还不明白,你可以倒过来做：把 1）The boys like China 2）THe boys are from America 两句改成定语从句.那么答案就是The boys who are from America like China
附：关系副词引导的定语从句关系副词可代替的先行词是时间、地点或理由的名词，在从句中作状语。
1）when, where, why
关系副词when, where, why的含义相当于介词+ which结构，因此常常和介词+ which结构交替使用，例如：
There are occasions when （on which） one must yield. 任何人都有不得不屈服的时候。
Beijing is the place where （in which） I was born. 北京是我的出生地。
Is this the reason why （for which） he refused our offer? 这就是他拒绝我们帮助他的理由吗？
2）that代替关系副词
that可以用于表示时间、地点、方式、理由的名词后取代when, where, why和介词+ which引导的定语从句，在口语中that常被省略，例如：
His father died the year （that / when / in which） he was born. 他父亲在他出生那年逝世了。
He is unlikely to find the place （that / where / in which） he lived forty years ago. 他不大可能找到他四十年前居住过的地方。
同位语从句讲解与练习
1．定义：用作同位语的从句叫做同位语从句。
2.用法：同位语从句的先行词多为fact, news, idea, thought, question, reply, report, remark等，关联词多用从属连词。如： 1. 连词that引导同位语从句
（注：引导同位语从句的不能省略）
The idea that you can do this work well without thinking is quite wrong.你认为不动脑筋就能做好这件工作的想法是完全错误的。（作idea的同位语）
【注意1】在某些名词(如demand, wish, suggestion, resolution等)后面的同位语从句要用虚拟语气
There was a suggestion that Brown should be dropped from the team. 有一项建议是布朗应该离队。
【注意2】引导同位语从句的连词that通常不省略
He gabbed his suitcase and gave the impression he was boarding the Tokyo plane. 他拿起了手提箱，给人的印象是他要登上飞往东京的飞机了。
2. 连词whether引导同位语从句 （注：if不能引导同位语从句）
The question whether we should call in a specialist was answered by the family doctor. 我们是否请专家由家庭医生来定。
附：其它引导词引导的同位语从句连接代词what, who, whom, whose, which引导同位语从句
1).I have no idea what size shoes she wears.我不知道她穿几号的鞋。（what作定语）
2).I have no idea which wine is best—it’s a matter of personal taste.我不知道哪种酒最好，这是个人口味的问题。（which作定语）
3) question who will take his place is still not clear. （who作主语）
4. 连接副词引导同位语从句 连接副词when, where, how, why
We haven’t yet settled the question where we are going to spend our summer vacation.
1．that引导的同位语从句与定语从句之区别
that引导的同位语从句/that引导的定语从句
1）句法
that只起连接从句的作用，无意义。在从句中不充当句子成分。不可省。
that替代先行词在从句中不仅起连接作用，还充当一个句子成分。如在从句中作动词的宾语时可省略。
2）意义上
从句是被修饰名词的内容。从句起限定作用，是定语
The news that Mr. Li will be our new English teacher is true. (同位语从句，that不可省)
The news (that) he told me yesterday is true. (定语从句，that在从句中作的宾语，可省)
2．一些表示“建议、命令、要求”的名词后所跟的同位语从句中，谓语动词用虚拟语气should+动词原形表示。should可省。如：
This is our only request that this (should) be settled as soon as possible.
