当定语从句的主句只有一个先行词时,怎样来划分主从句的句子成分?如：The man who is reading is m

who is reading是定语从句,修饰 the man【主句】The man is my dad。主系表结构主语是the man,系动词是is,表语是my dad【从句】who is reading主语who代替the man做主语,谓语动词是is reading现在进行时总起来翻译就是：正在看书的那个人是我的爸爸。