题目内容：

阅读下面材料，在空白处填入适当的内容（1个单词）或括号内单词的正确形式。

A castle is a type of fortified（加固的）structure    1.    (build) in Europe and the Middle East during the Middle Ages. This is different from a palace     2.    is not fortified, though there are a large number of     3.    (similarity) among these types of construction. Since then usage of the term     4.    (apply) to diverse structures.

The European castles        5.   (origin) in the 9th and 10th centuries, resulting in its land divided among nobles, who built castles to control the area    6.   (surround) them. The castles were also    7.  (defense) structures. Although army uses are often emphasized in castle studies, the structures also served      8.  centers of administration and symbols of power. Urban castles were   9.  (usual) used to control the local people and important travel routes, 10.  rural castles were often built near farmland.