在定语从句中,什么时候只能用that 引导从句?

(1).先行词是不定代词all,few,little,much,something,nothing,anything等
eg:All that we have to do is to practise every day.
Little that he said is believable.
(2).先行词被序数词或者形容词最高级所修饰
eg:The first lesson that I learned will never be forgotten
(3).先行词被all,any,every,each,few,little,no,some等修饰
eg:Every means that had been tried proved to be useless.
I read all the books (that) you gave me.
(4).先行词被 the only,the very,the right,修饰时
eg:He is the only person that I want to talk to
This is the very book (that) I'm looking for.
(5).先行词既有人又有物时
eg:They talked of things and persons that they remembered in the school
(6).在定从中,如果一个从句用who或者which引导时,那么另一个从句用that (已经有了who/which时,为了避免重复)
eg:He is the student that I have ever seen who can jump highest.
My brother studies in the school which is the mot beautiful in our city that isn't far from here.