下列VB程序运行时，单击命令按钮Command1后，文本框显示的内容是
Private Sub Command1_Click()
a = 2
b = 2
Do While a <= 4
a =" a" * b
b =" a" * b
Loop
Text1.Text = Str(a)
Text2.Text = Str(b)
End Sub
Text1中显示               , Text2中显示                   。