在窗体上画一个命令按钮和两个文本框，其名称分别为Command1、Text1和Text2，在属性窗口中把窗体的KeyPreview属性设置为True，然后编写如下程序：
Dim S1 As String,S2 As String
Private Sub Form_Load()
Text1.Text=" "
Text2.Text=" "
Text1.Enabled=False
Text2.Enabled=False
End Sub
Private Sub Form_KeyDown(KeyCode As Integer,Shift As Integer)
S2=S2&Chr(KeyCode)
End Sub
Private Sub Form_KeyPress(KeyAscii As Integer)
S1=S1&Chr(KeyAscii)
End Sub
Private Sub Command1_Click()
Text1.Text=S1
Text2.Text=S2
S1=" "
S2=" "
End Sub
程序运行后，先后按“a”、“b”、“c”键，然后单击命令按钮，在文本框Text1和Text2中显示的内容分别为( )
A．abc和ABC
B．空白
C．ABC和abc
D．出错
