where是关系副词，在定语从句中充当地点状语，相当there;而which是一个关系代词，在定语从句中充当主语或宾语，相当于一个代词。如:This is the factory -----his father worked ten years ago.在这个句子中，-----his father worked ten years ago部分，缺少了worked的地点状语，所以用关系副词where。再看一个句子：This is the factory -----his father worked in ten years ago.在-----his father worked in ten years ago中，缺少了介词的宾语，所以用关系代词whic...
关系词只能用which，而不用that 的情况：a.先行词为that， those时，用which， 而不用that.例如：What’s that which is under the desk？ 在桌子底下的那些东西是什么？b.关系代词前有介词时，一般用which，而不用that.例如：This is the...
