what day is it today后跟It's Monday.还是Today is monday.

问题描述:

what day is it today后跟It's Monday.还是Today is monday.

都可以。
It 指代的就是Today,
所以你给的两个答句是一样的。
后面那句Monday的M要注意大写。
星期几的都要大写。。

都可以,前一个更常用。

前者

It's Monday.