Private Sub Form_Load()
Dim startDate
Dim nowDate
Dim interval As Long
Dim dutyMan As Integer
Dim order(0 To 2) As String
order(0) = "【张某】"
order(1) = "【王某】"
order(2) = "【刘某】"
startDate = DateSerial(2018, 5, 8)
nowDate = Date
interval = nowDate - startDate
dutyMan = interval Mod 3
Label1.Caption = "今天是" & Date & ",该" & order(dutyMan) & "值班"