dtd 内容
<!ELEMENT students (student+)>
<!ELEMENT student (name,age,语文成绩,数学成绩)>
<!ELEMENT name (#PCDATA)>
<!ELEMENT age (#PCDATA)>
<!ELEMENT 语文成绩 (#PCDATA)>
<!ELEMENT 数学成绩 (#PCDATA)>
<!ATTLIST sutdent classID ID #REQUIRED>
<!ATTLIST 语文成绩 teacher CDATA #REQUIRED>
<!ATTLIST 数学成绩 teacher CDATA #IMPLIED>

xml 文件内容
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE students SYSTEM "student.dtd">
<students>
        <student classID="itcast_1009">
                <name>zhangsan</name>
                <age>18</age>
                <语文成绩 teacher="lisir">98</语文成绩>
                <数学成绩 teacher="cuisir">100</数学成绩>
        </student>
        <student classID="itcast_1001">
                <name>pn</name>
                <age>26</age>
                <语文成绩 teacher="shiSir">130</语文成绩>
                <数学成绩 teacher="cuiSir">150</数学成绩>
        </student>
        <student classID="itcast_1002">
                <name>wangwu</name>
                <age>22</age>
                <语文成绩 teacher="zhangSir">100</语文成绩>
        </student>
</students>

错误提示：
warning: Element 'sutdent' was referenced in an attlist but never declared
Attribute 'classID' is not declared for element 'student'
Not enough elements to match content model : '(name,age,语文成绩,数学成绩)'


求解！！！！！！

dtd 内容
<!ELEMENT students (student+)>
<!ELEMENT student (name,age,语文成绩,数学成绩)>
<!ELEMENT name (#PCDATA)>
<!ELEMENT age (#PCDATA)>
<!ELEMENT 语文成绩 (#PCDATA)>
<!ELEMENT 数学成绩 (#PCDATA)>
<!ATTLIST sutdent classID ID #REQUIRED>
<!ATTLIST 语文成绩 teacher CDATA #REQUIRED>
<!ATTLIST 数学成绩 teacher CDATA #IMPLIED>

xml 文件内容
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE students SYSTEM "student.dtd">
<students>
        <student classID="itcast_1009">
                <name>zhangsan</name>
                <age>18</age>
                <语文成绩 teacher="lisir">98</语文成绩>
                <数学成绩 teacher="cuisir">100</数学成绩>
        </student>
        <student classID="itcast_1001">
                <name>pn</name>
                <age>26</age>
                <语文成绩 teacher="shiSir">130</语文成绩>
                <数学成绩 teacher="cuiSir">150</数学成绩>
        </student>
        <student classID="itcast_1002">
                <name>wangwu</name>
                <age>22</age>
                <语文成绩 teacher="zhangSir">100</语文成绩>
        </student>
</students>

错误提示：
warning: Element 'sutdent' was referenced in an attlist but never declared
Attribute 'classID' is not declared for element 'student'
Not enough elements to match content model : '(name,age,语文成绩,数学成绩)'


求解！！！！！！