但that 一般可用來代替who， whom， which，作賓格時可省略
    Do you remember the teacher that/who taught us English?
    A bookstore is a store that/which sells books.
    The man (that/whom/who) you know is a famous professor.
    A) that 不能用來替代who， whom， which的兩種情況
    1)“介詞+whom/which”的結(jié)構(gòu)中，不能用that
    She is a good student from whom we should learn.
    2) 在非限制性定語從句中，逗號后面不能用that
    She sang a new song， which we like very much.
    注意：非限制性定語從句的關(guān)系代詞不能省略
    B) 用that不用which的一些特殊情況
    1) 先行詞為all， much， little， something， anything， everything， nothing等
    Is there anything (that) I can do for you?
    2) 先行詞前有形容詞級修飾
    This is the most exciting report that I have ever read.
    3) 先行詞前有first， last， next， only， very， all， any等詞修飾
    The first step (that) we are to take is very difficult.
    4) 先行詞同時含有“人”和“非人”時，用that 不用which，也不用who/whom
    He talked about the people and the books that interested him.
    C) 關(guān)系副詞when， where， why
    用關(guān)系副詞when時，它的先行詞是表示時間的名詞，用where時先行詞是表示地點的名詞，而用why時它的先行詞只可能是reason，使用時應(yīng)注意以下幾點：
    1) 關(guān)系代詞的選擇主要是看先行詞在從句中所作的成分
    This is the city where I was born.
    This is the city (which/that) he has visited
    I don‘t know the reason why she is late.
    That is the reason (which/that) everybody knows
    Do you still remember the day when he arrived?
    Do you still remember the day (that/which) we spent together?
    2) 關(guān)系副詞when，where， why可由“介詞+which”的結(jié)構(gòu)來替代
    Is this the reason for which they came?
    He left the day on which I came.
    注意：how 不能用來引導(dǎo)定語從句
    This is the way how he did it.
    D) As 作關(guān)系代詞的用法
    與the same， such連用
    This is the same book as I read last week.
    Such books as I have read are classical works.