Private Sub Worksheet_Change(ByVal Target As Range)
Dim ce As Range
If Intersect(Target, Range("A2:A100000")) Is Nothing Then Exit Sub ' Neu cot A khong thay doi thi thoat
For Each ce In Target 'truong hop 1 hoac nhieu o cung thay doi: Duyet qua tung o
If ce.Value <> "" Then ce.Offset(, 1) = Date
Next
End Sub