These are the days in which it takes two salaries for each home,but divorces increase;

These are the days in which it takes two salaries for each home,but divorces increase;
现在每个家庭都可以有双份收入,但离婚的现象越来越多了；
谁帮我分析下里面的 the days in which 我认为它不加in也是对的,虽然in these days 是个短语,但是不用in 好象也可以说的通.改为these are the days which it takes two salaries for each home.这样which直接做days的宾语.然后里面的it 指的是什么?哪为大虾给纤细分析下.
那我想知道为什么句子中these are the days 后跟的是in which in which 不是等于where 那句子不就不通了吗？