1. (2021·湖州模拟) 有如下VB程序段：

s1 = "2019GaoKao"

For i = 1 To Len(s1)

    ch = Mid(s1, i, 1)

    If ch >= "0" And ch <= "9" Then

        ch = Str((Val(ch)+1) Mod 10)

        s2 = ch + s2

    ElseIf ch >= "a" And ch <= "z" Then

        ch = Chr(Asc(ch) - 32) s2 = s2 + ch

    End If

Next i

该程序运行后，s2的值是（     ）