—You haven't been to China Pavilion at World Expo in Shanghai, have you?        

—             . I really hope to visit it some day.[ ]

A. Yes,I have                              

B. No, I haven't            

C. Certainly, I haven't                      

D. No, I have

有一个VBA计算程序的功能如下，该程序用户界面由4个文本框和3个按钮组成。4个文本框的名称分别为：Text1、Text2、Text3和Text4。3个按钮分别为：清除(名为Command1)、计算(名为Command2)和退出(名为Command3)。窗体打开运行后，单击清除按钮，则清除所有文本框中显示的内容；单击计算按钮，则计算在Text1、Text2和Text3三个文本框中输入的3科成绩的平均成绩并将结果存放在Text4文本框中；单击退出按钮则退出。请将下列程序填空补充完整。
Private Sub Command1_Click( )
Me!Text1 = ""
Me!Text2 = ""
Me!Text3 = ""
Me!Text4 = ""
End Sub
Private Sub Command2_Click( )
If Me!Text1 = "" Or Me!Text2 = "" Or Me!Text3 = "" Then
MsgBox "成绩输入不全"
Else
Me!Text4=( (13) +Val(Me!Text2)+Val(Me!Text3))/3
(14)
End Sub
Private Sub Command3_Click( )
DocmD1 (15)
End Sub