Taking regular exercise is a good habit ,___ my grandfather formed in his childhood.
问题描述：
Taking regular exercise is a good habit ,___ my grandfather formed in his childhood.
这个题为什么要填one 而不是what?
答
Taking regular exercise is a good habit ,one (that) my grandfather formed in his childhood.
逗号后面的是不定代词短语用作habit的同位语,而省略掉的that引导了一个定语从句修饰one这个先行词.