worksheets 和 sheets 的不同

注意两者的区别：

遍历sheets

Sub 遍历sheets下的所有对象()
For Each shs In Sheets
    k = k + 1
    Cells(k, 1) = shs.Name
Next
End Sub

遍历worksheets

Sub 遍历worksheets下的所能对象()
For Each shs In Worksheets
    k = k + 1
    Cells(k, 2) = shs.Name
Next
End Sub