白磷着火点为40℃，红磷着火点为240℃，它们在空气中燃烧都生成有毒的白烟﹣﹣五氧化二磷，五氧化二磷易溶于水．

—The blouse is very nice. I'll take it.

—But you'd better ________ first. I think it is a little large for you.

Function s(m) As Boolean

 Dim i As Integer

 ______1_______

For i = 2 To Int(Sqr(m))

 If m / i = 0 Then  s = false     ‘3

Next i

End Function

Private Sub Command1_click()

 Dim i, n As Integer

 Dim p1, p2 As Boolean

  n = Val(Text1.Text)

  p1 = s(3)

  List1.Clear

  For i = ______2_____

  p2 = s(i)

  If p2 = True Then List1.AddItem = Str(i - 2) + " " + Str(i)   ‘4

  p1 = p2

Next i

End Sub