主题：解释代码

For Each fl As String In fls

    Dim dr As DataRow = DataTables("组题方式").Find("[试题] = '" & fl & "'")

    '组合字符串

    str = str & " or [分类] = '" & fl & "' And [组题] <= " & dr(Vars("车型"))*100

Next '筛选

可以这样测试一下，看效果

Dim Str As String

for i as integer = 0 to 2

str = str & " or 第一列=" & i

next

msgbox("没有去掉前的结果是：" & str)

msgbox("去掉后的结果是：" & str.SubString(4))