Around the world， people live in homes of many shapes and sizes． In some countryside， people live together with their family in a huge house with gardens or backyards． On the other hand， the buildings in cities are usually very close together．

    A home can be any kind of building﹣ large or small． Some people even have homes on boats， in tents or in caravans that can be moved around． Caravans are mobile homes． They are towed（拖，拉） by either a car or a huge truck． Some of them are holiday homes． We can see many families staying together in these caravans．

    In the past， rich and important people built strong castles to keep their families safe． The castles（城堡） were built on hill tops with high walls and some even had moats． Moats were deep and wide ditches（壕沟） filled with water． They made it difficult for enemies to attack．

    Today， we have different ways of protecting our homes． Some homes are installed（安装） with video cameras and an alarm system． These will help to alert（向……报警） home owners if someone tries to break in．

    Homes are important to all the people． Everyone needs a home where they feel sheltered and safe．

（1）How are the buildings in cities？　　

（2）What is used to tow the caravans？　　

（3）Who built castles to keep their families safe in the past？　　

（4）Why were moats built？　　

（5）What do people use to protect their homes today？