Dim a(4) As Integer

Private Sub Command1_Click()

 Dim s As String

a(1)=10:a(2)=30:a(3)=20:a(4)=40

 s=doit(4)

 Label1.Caption=s

End Sub

Function doit(k As Integer) As String

 If k=1 Then

  doit=Str(a(1))

  Else

  doit=doit(k-1) & Str(a(k))

 End If

End Function

程序运行后,标签Label1中显示的内容是（  ）

Function fact(n As Integer) As String

If n = 1 Then

    fact = fact & 1

Else

    fact = fact(n \ 2) & n Mod 2

End If

End Function

Private Sub Command1_Click()

Dim x As String, i As Integer, r As Integer

x = Text1.Text

For i = 1 To Len(Text1.Text)

If Mid(x, i, 1) = "." Then Exit For Next i

r = Val(Mid(x, i + 1, Len(Text1.Text) - i)) Text2.Text = fact(r)

End Sub

在文本框Text1中输入2019.70，则执行程序段，在文本框Text2中显示的内容是（  ）

Dim i As Integer, sum As Integer

Dim a(1 To 6) As Integer, b(1 To 6) As Integer

sum = 0

a(6) = 18: a(5) = 7: b(6) = 14: b(5) = 16

For i = 4 To 1 Step -1

 a(i) = a(i + 2) - a(i + 1)

 b(i) = b(i + 2) - a(i)

 If b(i) Mod 3 = 0 Then sum = sum + b(i)

Next i

Text1.Text = Str(sum)

该程序段运行后，文本框Text1中显示的内容是（  ）

F(1)=3

F(n)=F(n-1)*2

def f(n):

    if n == 5:

        return ___①___

    else:

        return _____②____

print(___③___)