使用VBA比较两个不同工作簿中的两列

Question

下面的代码是在一个特定的范围内用两张纸（Sheet1，Sheet2）写在一个工作簿中的。

Sub CheckAvailability()
   Dim rMyRng As Range, rCompare As Range, r As Range, lFound As Long, 
   blStatus As Boolean

   Application.ScreenUpdating = False

   With Sheets("Sheet1")
      Set rMyRng = .Range("A1:B" & Range("B" & Rows.Count).End(xlUp).Row)
   End With

   With Sheets("Sheet2")
      Set rCompare = .Range("A1:B" & Range("B" & Rows.Count).End(xlUp).Row)
   End With

   For Each r In rMyRng.Rows
      With r
        .Select
         blStatus = False
         lFound = Application.CountIfs(rCompare.Columns(1), .Cells(1).Value, 
         rCompare.Columns(2), .Cells(2).Value)
         If lFound Then blStatus = True
             .Cells(2).Offset(, 1).Value = blStatus
      End With
 Next r

 Application.ScreenUpdating = True

我该如何调整它以使其能够与两张具有动态变化的行的工作表一起使用？