An apple a day keeps the doctor away. 一天一苹果，不用请医生。
活学活用：apple
as like as an apple to an oyster 毫无相同之处
The rotten apple injures its neighbours. [谚]一只烂, 烂一筐; 一个坏朋友可以影响一群好人。
Throw away the apple because of the core. 因噎废食。
upset sb.‘s apple cart 破坏某人计划
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An Apple a day keeps the doctor away
原文：http://www.cnblogs.com/zhangzujin/p/3811971.html