短文改错。

     假定英语课上老师要求同桌之间交换修改作文，请你修改你同旧式写的以下作文。文中

共有10处语言错误，每句中最多有两处。错误涉及一个单词的增加、删除或修改。

     增加：在缺词处加一个漏字符号（∧），并在其下面写出该加的词。

     删除：把多余的词作斜线（\）划掉。

     修改：在错的词下划一横线，并在该词下面写出修改后的词。

     注意：1. 每处错误及其修改均仅限一词；

               2. 只允许修改10处，多者（从第11处起）不计分。

     We'll never forget the day that my classmates and I paid a visit of a chemistry factory last Sunday. It

was a large one with nearly 20,000 workers. It looks like a garden and we could see colorful flowers, grass

and trees anywhere. We also visited some workshops and saw the workers working hard.We talked to them

and had learned a lot. We understood them farther. On the way home we felt tiring.But we both thought we

had very good day. We really hoped that we could get many chances of leaving the school and learning social

experiences.

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在窗体中添加一个名称为C1的命令按钮，然后编写如下事件代码：

Private Sub C1_Click()

str＝"ABAABAAABABBA"

For i＝6 To 2 Step-2

x＝Mid(str,i,i)

y＝Left(str,i)

z＝Right(str,i)

Next i

MsgBox x&y&z

End Sub

单击命令按钮，则消息框的输出结果是( )。

A．ABBAAB

B．ABBABA

C．BABABA

D．BAABBA