【正确答案】 D

【答案解析】[解析] 野生动物在动物园里被关进笼子。limited有限的。如：We had only limited communion with the natives．我们与本地人的交往有限。bounded有界的。如：The bounded area is typically either a business office environment or a residential environment．此封闭地区是典型的商业办公室环境或居住的环境。restricted限制。如：I restrict myself to smoking two cigarettes a day. 我限定自己每天只抽两支烟。confined被限制的。最符合题意。如：After her operation，she was confined to bed for a week. 她手术之后已卧床一星期了。