第21题: [单项选择]Crisis would be the right word to describe the in many rare animal species. A. restriction B. descent C. decline D. minimization 参考答案:C 答案解析:此题考查名词的用法。C项decline意为“(量)逐渐减少;临近消亡”,符合题意。A项restriction意为“限制;约束”。B项descent意为“下降;下倾”。D项minimization意为“