he works in a city which/that is far from the village!

题目

he works in a city which/that is far from the village!
这里的which/ that 的作用,能不能用where啊
what most parents fail to realize,_____,is that today`s children lack
这里为什么可以填 though 啊 ,实在想不通,求英语达人大神们求解啊

答案