请英语好的同学帮忙教我一下这几道关于定语从句的题目，谢谢~

Question

改错题：

He has two sons,each of them lookks like him.

Please pass me the book that cover is red.

填空题：

He paid the boy 10dollars for washing ten windows,most( )hadn’t been cleaned for at least a year.

最好是能附上讲解，如果不愿打的话就算了，我自己也能理解~非常感谢！

Answer 1

改错题：
He has two sons,each of them lookks like him.
改成定语从句：
He has two sons,each of whom lookks like him.
理由：
两句话之间不能用逗号来连接，必须用关系词和连词来连接。因此把each of them改成了each of whom

Please pass me the book that cover is red.
Please pass me the book whose cover is red.
表示所属关系的关系代词不能用that,而要用whose;whose表示先行词the book和cover之间的所属关系“是这本书的封面”
whose的先行词可以是“人”，也可以是“物”。

填空题：
He paid the boy 10 dollars for washing ten windows,most(of which )hadn’t been cleaned for at least a year.
关系代词which的先行词是ten windows.
most of which=most of the ten windows

of是介词，在介词后面关系代词不能用that,表示“人”用whom;表示“事”或“物”用which.
在这里表示“物”，用which

Answer 2

He has two sons,(and) each of them looks like him.

前后是两个单独的句子，需要用连词连接，这里就用and.

Please pass me the book that(替换成whose） cover is red.

cover是名字，本身就可以作主语了，所以前面的先行代词需要有修饰作用。翻译移过来就是谁的封皮是红色的，如果只是that，后面句子就不应该有主语了。

填空题：

He paid the boy 10dollars for washing ten windows,most( of which )hadn’t been cleaned for at least a year.

大部分已经有超过一年没被擦过了。most 表示大部分并且后面接名词的时候要加of, which指代前面的玻璃，因为前面有介词of,所以不可以用that

Answer 3

He has two sons,each of them looks like him.
应该是both of them两个都是重点在“大家一致”，而不是each of重点在“各有不同”。
Please pass me the book that cover is red.
应该是which cover is red,that可以引导定语从句。一般that和which可以互用，只能用which的情况（只讨论which that）就是非限制性定语从句，其他情况都可以用that。
He paid the boy 10dollars for washing ten windows,most(of which )hadn’t been cleaned for at least a year.
most of which 是用来引导定语从句的.

Answer 4

改错题1 he has two sons和each of them looks like him均为完整的句子，所以不能放在同一句子（除非有连接词或者使用定语引导词）所以可以改为he has two sons,and each of them looks like him.或者he has two sons,each of whom looks like him.
改错题2 cover是名词，所以前面不能用that,而是应该用形容词性引导词，所以应该改为please pass me the book whose cover is red.
填空题 大部分已经有超过一年没被擦过了。most 表示大部分并且后面接名词的时候要加of, which指代前面的玻璃，因为前面有介词of,所以不可以用that