根据语法和文章的上下文意思填入所缺单词。

    Animals are ____ (people) friends. But many wild animals are ____(face) the danger of____(die) out. There're many reasons. First, their living environment change a lot because of the ____(develop) of many cities. Also, ____(pollute) becomes worse and this make wild animals lose ____homes. Second, some people are killing animals ____getting their fur, skin, teeth and meat.

    People should do something to help protect ____(endanger) wild animals. For example, people can build some nature reserves to save wild animals' homes. Animals can live ____(free) there. Besides, people are not allowed ____kill wild animals. If we start protecting our animal friends, our world will become much better.