关于一个话题写一小段英文不要机器翻译在线等

Animals are our friends, We should not cage them.
I went to the zoo from time to time, whenever I came back from wathcing them in cages, I feel very bad. For example, I never heard the lion roar.They are our friends they shoudn't be caged only for our happiness. Although they are alive, but I konw they are not happy. We should let them out back to the nature.