a = a * b

b = a / b

a = a / b

实现上述功能的VB程序如下，请回答下列问题。

Private Sub Command1_Click()

   Dim i As Integer, n As Integer, m As Integer

   Dim num As Integer, t As Integer

   Dim a(1 To 100) As Boolean

   n = Val(Text1.Text)

   m = Val(Text2.Text)

   For i = 1 To n

      a(i) = True

   Next i

       ①      

   Do While t > 1

      For i = 1 To n

        If a(i) = True Then   ②    

        If num = m The

               ③     

t = t - 1

           num = 0

           Text3.Text = Text3.Text + Str(i)

        End If

      Next i

   Loop

   For i = 1 To n

       If a(i) = True Then Label2.Caption ="获得礼品同学编号:" + Str(i)

   Next i

End Sub

Private Sub Command1_Click()

Dim x As Integer,y As Integer,z As Integer

x=Val(Text1.Text)     ‘第1个正整数

y=Val(Text2.Text)     ‘第2个正整数

                   ‘调用函数gcd

Text3.Text=Str(z)

End Sub

Function gcd(a As Integer, b As Integer) As Integer

 Do While a <> b

If a>b Then a=a-b Else b=b-a

Loop

gcd=b

End Function

方框中的正确语句是（  ）

count=0

For i=1 To 20

    a(i) =Int(Rnd*100) + 1

Next i

For i= 1 To 20

    ①

Next i

For i= 1 To 100

    If b(i) <> 0 Then count =count+1

Next i

Label 1.caption=“不重复数字个数”+Str(count)

为实现上述功能，则程序①处应填入的语句为（  ）

i=0

while i<6:

   print

   i=i+1

>>> a=8

>>> b=2

>>> a-=b

>>> b+=a

>>> a+b