Private Sub Command1_Click()

x = Text1.Text

n = Len(x)

s=s+Mid(x,1,1)

For i = 2 To n

flag =0

For j = 1 To Len(s)

If  Then '{#blank#}1{#/blank#}

flag = 1: Exit For

End If

Next j

If  Then '{#blank#}2{#/blank#}

s = s + Mid(x, i, 1)

End If

Next i

Text2.Text = s

End Sub

Dim i As Integer， a As Integer， b As Integer， c As Integer

Dim s As String

a = 0: b = 1: c = 0: i = 2

s = Str(a) + Str(b)

Do While c <= 10000 And i < 100

    a = b: b = c

    c = a + b

    s = s + Str(c)

    i = i + 1

Loop

Text1.Text = s

运行上面的程序，发现输出的数列不正确，应进行修改。以下修改正确的是（  ）

查找的英文单词由连续的ASCII英文字符（a～z或A～Z）组成。组合词程序会进行分解，如river-small可拆分为2个单词river和small，查找的英文单词不区分大小写。程序代码如下，但加框处代码有错，请改正：

Private Sub Command1_Click()

Dim article As String,f As String,count As Integer

Dim i As Intege，,begin As Integer,s As String

article=Text1.Text : f=Text2.Text : count=0

begin = 1

For i=1 To Len(article)

   t = Mid(article,i,1)

   If Not(t>="A"And t<="Z" Or t>="a" And t<="z") Then

     If i > begin Then

        s =      '①

        If LowerCase(f)=LowerCase(s) Then

            count = count+1

        End If

      End If

          begin = i + 1

     End If  

  Next i

    Text3.Text=Str(count)

End Sub

Function LowerCase(word As String) As String    '单词转化为全小写的形式

Dim i As Integer,c As String

For i=1 To Len(word)

   c = Mid(word,i,1)

   '小写英文字母的ASCII码值比大写字母的值大32

   If c>="A" And c<="Z" Then c =    '②

   LowerCase = LowerCase + c

Next i

End Function

以上程序段运行时，为了实现上述功能，加框处代码应改正为：

①{#blank#}1{#/blank#}；②{#blank#}2{#/blank#}。

小明现想用Python输出所有的多选题的选项组合，他用4位二进制数模拟所有选项组合(1-选，0-不选），再从中筛选出有效组合，例如1100是一种有效组合，1000是一种无效组合。

实现该功能的Python程序如下：

xx=["A","B","C","D"]

combs=[]

i=0

while     ①    :

t=i

s=""

c=0

    for j in range(4):

       if t%2==1:

          s=   ②      

c+=1

            ③      

    if     ④      :

       combs.append(s)       # append()方法用于在列表末尾添加新的对象。

i+=1

print("符合要求的选项组合：")

print(combs)