xml中出现“文档中根元素后面的标记必须格式正确。”的错误

<?xml version="1.0" encoding="GB2312" standalone="no"?>
<time>//如果这里和结尾的</time>不加，就会出现如题的错误
<monday>
<playGameTime>5.0</playGameTime>
<studyTime>3.0</studyTime>
<readTechnologyTime>0.0</readTechnologyTime>
<officialTime>0.0</officialTime>
<otherTime>0.0</otherTime>
<efficiency>0.0</efficiency>
<state>ok</state>
</monday><tuesday>
<playGameTime>5.0</playGameTime>
<studyTime>3.0</studyTime>
<readTechnologyTime>0.0</readTechnologyTime>
<officialTime>0.0</officialTime>
<otherTime>0.0</otherTime>
<efficiency>0.0</efficiency>
<state>ok</state>
</tuesday>
</time>