GPT答：

7i24.cn

Sub 读取文件夹中所有文本文件并替换作业()

Dim FolderName As String
FolderName = InputBox("请输入文件夹的全路径：")

Dim FileName As String
FileName = Dir(FolderName & "\*.*", vbNormal)

Do While FileName <> ""

    If Right$(FileName, 3) = "txt" Then
        Dim FPath As String
        FPath = FolderName & "\" & FileName
        Dim txtContent As String
        Open FPath For Input As #1
        txtContent = Input(LOF(1), #1)
        Close #1
        txtContent = Replace(txtContent, "作业", "作文")
        Open FPath For Output As #1
        Print #1, txtContent
        Close #1
    End If

    FileName = Dir

Loop

MsgBox ("内容已替换！")

End Sub