请在下列程序代码的基础上按照要求设计该程序, 完善程序中的划线部分。

Dim n As Integer, a1 As Integer, a2 As Integer, a3 As Integer

Function f(x) As Boolean

f = True

      For i = 2 To Sqr(x)

         If x Mod i = 0 Then      ①     

Next i

End Function

Private Sub Command1_Click()

n =      ②       

For a1 = 2 To n

 For a2 = a1 To n

  For a3 = a2 To n

   If     ③      And f(a1) And f(a2) And f(a3) Then

    List1.AddItem (Str(a1) + " " + Str(a2) + " " + Str(a3))

   End If

  Next a3

 Next a2

Next a1

End Sub

其中①处填入{#blank#}1{#/blank#}；②处填入{#blank#}2{#/blank#}；③处填入{#blank#}3{#/blank#}

Dim a(1 to 5) as Integer, i as Integer, c as Integer

a(1) = 2 : a(2) = 1 : a(3) = 3 : a(4) = 4 : a(5) = 5

c = 0

For I = 3 to 5

If a(i - 2) + a(i - 1) = a(i) Then c = c + 1

Next i

Text1.Text = Str(c)

该程序运行后，文本框text1中显示的内容是（  ）

For i = 100 To 999 lag = True: j = 2

Do While j < i And flag

Loop

If flag Then List1.AddItem Str(i) Next i

方框中的代码由以下四部分组成：①End If   ②If i Mod j = 0 Then   ③j = j + 1

④flag = False。代码顺序正确的是（  ）

Private Sub Command1_Click()

    Dim c As Integer, n As Integer c = 0 : n = 9

    Do While n <= 1000

        If n Mod 3 = 2 And n Mod 5 = 3 Then

            List1.AddItem Str(n)

            c ={#blank#}1{#/blank#}

        End If

        n ={#blank#}2{#/blank#}

    Loop

    Label1.Caption = "1000 以内满足条件的数有" & Str（c）& "个"

End Sub

程序运行时，先随机生成15个[1，30]区间内的整数，存储在数组a(0)至a(14)，并在文本框Text1中显示；单击“计算”按钮Command1，则在标签Labe14中显示连续三数最大和，在标签Label5中显示连续三数最小和，程序运行界面如图所示。

实现上述功能的VB程序如下，请在划线处填入合适的代码。

Const n=14

Dim a(n) As Integer

Private Sub Form_Load()

'随机生成15个数,存储在数组元素a(0)～a(14)中,并显示在文本框Text1中

End Sub

Private Sub Command1_Click()

    Dim i As Integer, j As Integer, k As Integer

    Dim imax As Integer, imin As Integer

    Dim smax As Integer, sum As Integer, smin As Integer

    smax=0:smin=100

    For i=0 To 14

        j= {#blank#}1{#/blank#}

        k= {#blank#}2{#/blank#}

        sum=a(i)+a(j)+a(k)

        If sum>smax Then

            smax=sum

            imax=i

        End If

        If sum<smin Then

            smin=sum

            imin=i

        End If

    Next i

    Label4.Caption=Str(smax)

    Label5.Caption=Str(smin)

End Sub