How i can make that go till lastrow.

sub rebeat()

If Range("B5") = 0 Then
Range("C5").Value = Range("A5")
ElseIf Range("B6") = 0 Then
Range("C6").Value = Range("A6")
ElseIf Range("B7") = 0 Then
Range("C7").Value = Range("A7")
ElseIf Range("B8") = 0 Then
Range("C8").Value = Range("A8")
End If

end sub