求助：我表格中有1/2/3这样命名的表，循环时Sheets("i")显示错误

Dim i As Integer, vb As Workbook
For i = 25 To 31
Set vb = Workbooks.open("F:\系统报表\8月\x08." & CStr(i) & ".xls")
Cells.Select
Selection.Copy
ActiveWindow.WindowState = xlMinimized
Sheets("i").Select
Cells.Select
Sheets("i").Paste
vb.Close True
Application.DisplayAlerts = False
Next i
End Sub