Xml 元素“的前缀xs”；xs:schema"；不受约束

我该如何处理这个错误呢？元素“xs:schema”的前缀xs未绑定。我尝试了不同的方法来添加目标名称空间，但似乎不起作用。有谁能帮忙吗？我在这里附上了我制作的XML和XSD文件：

XSD:

相应的XML文件是

<?xml version="1.0" encoding="UTF-8"?>

<breakfast_menu>

<food>

<name>Turfle waffles</name>

<price>$5.95</price>

<description>This two turfle which has 2 famous product  is with real choco and maple syrup</description>

<calories>650</calories>

</food>

<food>

<name>Strawberry Belgian Waffles</name>

<price>$24.6</price>

<description>Light Belgian waffles covered with strawberries and whipped cream</description>

<calories>900</calories>

</food>

<food>

<name>Berry-Berry Belgian Waffles</name>

<price>$4.78</price>

<description>Light Belgian waffles covered with an assortment of fresh berries and whipped cream</description>

<calories>400</calories>

</food>

<food>

<name>Fried Toast</name>

<price>$7.68</price>

<description>Thick slices made from our homemade wheat dough bread</description>

<calories>250</calories>

</food>

<food>

<name>Homestyle Breakfast</name>

<price>$7.95</price>

<description>Two eggs, bacon or sausage, toast, and England popular  hash browns</description>

<calories>1500</calories>

</food>

</breakfast_menu>

草皮华夫饼
$5.95
这两块草皮有两个著名的产品，是用真正的巧克力和枫糖浆制成的
650
草莓比利时华夫饼干
$24.6
覆盖草莓和鲜奶油的淡比利时华夫饼干
900
浆果比利时华夫饼干
$4.78
淡比利时华夫饼干，上面覆盖着各种新鲜浆果和鲜奶油
400
油炸土司
$7.68
用我们自制的小麦面团面包做成的厚片
250
家庭式早餐
$7.95
两个鸡蛋，培根或香肠，土司和英国流行的炸土豆条
1500

何时以及如何获得此错误。

<?xml version="1.0" encoding="UTF-8"?>

<breakfast_menu>

<food>

<name>Turfle waffles</name>

<price>$5.95</price>

<description>This two turfle which has 2 famous product  is with real choco and maple syrup</description>

<calories>650</calories>

</food>

<food>

<name>Strawberry Belgian Waffles</name>

<price>$24.6</price>

<description>Light Belgian waffles covered with strawberries and whipped cream</description>

<calories>900</calories>

</food>

<food>

<name>Berry-Berry Belgian Waffles</name>

<price>$4.78</price>

<description>Light Belgian waffles covered with an assortment of fresh berries and whipped cream</description>

<calories>400</calories>

</food>

<food>

<name>Fried Toast</name>

<price>$7.68</price>

<description>Thick slices made from our homemade wheat dough bread</description>

<calories>250</calories>

</food>

<food>

<name>Homestyle Breakfast</name>

<price>$7.95</price>

<description>Two eggs, bacon or sausage, toast, and England popular  hash browns</description>

<calories>1500</calories>

</food>

</breakfast_menu>