请分别说一下 what the date,what the day,what's the date,what day is it 这四个提问词的区别,

what the date is today?今天几号?
what's the date today?今天几号?
what the day is today?今天星期几?
what day is it today?今天星期几?我只是想知道那四个提问词分别是提问什么的，不在后面加任何单词，仅仅是what the date，what the day，what's the date，what day is it不加单词也是以上的意思what the date 问日期??what's the date ?问日期?what the day ?问星期几?what day is it?问星期几?那有一道题：——（）？——It's September 1st.A.What the dayB.What the dayC.What's the dateD.What day is it为什么要选C，而不能选A呢？回答是9月1日 是问日期所以问句是what's the date today?因为有date的句子表示问的是日期而不是星期几?如果是what the day is it today?回答就应该是 it's monday 今天星期一