多项选择题

A.DATEDIF("2019/9/23","2020/5/23",d)
B.DATEDIF("2019/9/23","2020/5/23","m")
C.DATEDIF("2020/5/23","2019/9/23","y")
D.DATEDIF("2019/9/23","2020/5/23","y")