1. (2021高二下·德清开学考) 某VB 程序段如下：

Dim a(1 To 5) As Integer, i As Integer

a(1) = 1: a(2) = 1

For i = 3 To 5

    a(i) = a(i - 1) + a(i - 2)

Next i

Text1 Text = Str(a(i - 1))

该程序段运行后，文本框Text1中显示的内容是（     ）