the one 用来代替前面特指的单数名词,有时可用that代替(尤其在有后置定语的情况下.
that=the+单数可数名词/不可数名词 代替前面出现的单数可数名词/不可数名词
the book on the desk is better than /the one under the desk
the populatin of china is larger than that of america.
that常与介词of 一起使用
再问： 什么时候用the one 不用that ，比如Is this factory () you visited last week? A that B where C the one D in which 此句中 为什么不选A 而选C
再答： 从句中the one与that的区别 在定语从句中 the one 是先行词 that是关系代词 如 this book is the one that you bought fot me . that 作定从中bought的宾语 可以省略 就等于 this book is the one you bought fot me This is the book that you bought for me . 变成疑问句 的 两道题 is this book-----you bought for me? A that B the one 答案是 B Is this the book-----you bought for me? A that B the one 答案是A 所以，你说的问句，应该是this is thefactory that you visited last week，然后把that省略，这里就只能选the one了。
