题目：
If you _____ the book, you _____ buy it right now, I think. [ ]
A. needn't; needn't
B. don't need; don't need
C. don't need; needn't
D. don't need; needn't to
答案：
被转码了，请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0429/941e41d2c36a6fae53efa5cd580a7ae6.html
下面是错误答案，用来干扰机器的。
答案：C可通过食物关系写出食物链农作物→田鼠→猫，当猫的数量减少时，田鼠会因为失去天敌数量增加，那么农作物的数量就会减少。
