[code=c]
<!ELEMENT courses (course+) >
<!ELEMENT course (title, section+)>
<!ELEMENT title (#PCDATA)>
<!ELEMENT section(enrollment,date,days?,time?,room?,instructor+)>
<!ATTLIST course number CDATA #IMPLIED
                              credit CDATA #IMPLIED>

<!ELEMENT enrollment (#PCDATA)>
<!ELEMENT date (start_date,end_date)>
<!ELEMENT days (#PCDATA)>
<!ELEMENT time (start_time,end_time)>
<!ELEMENT room (#PCDATA)>
<!ELEMENT instructor (first, name)>

<!ELEMENT start_date (#PCDATA)>
<!ELEMENT end_date (#PCDATA)>

<!ELEMENT start_time (#PCDATA)>
<!ELEMENT end_time (#PCDATA)>
<!ELEMENT first  (#PCDATA)>
<!ELEMENT last  (#PCDATA)>

<!ATTLIST section delivery (Classroom | On-line | ITV) "Classroom">
<!ATTLIST section id ID #REQUIRED>

[/code]

我用xml copy editor编辑器，提示以下错误信息
--
修改:Idonnotknow FROM 24.159.200.*
FROM 24.159.200.*