An apple a day keeps the doctor away .中的Keeps为什么要加S?

An apple a day keeps the doctor away .中的Keeps为什么要加S? An apple a day keeps the doctor away为什么doctor不加s An apple a day keeps the doctor away.An apple a day that’s w 英语翻译:eat an apple a day keeps the doctor away. Eat an apple a day keeps the doctor away. An apple a day keeps the doctor away 啥意思 翻译:"an apple a day keeps the doctor away.'' An apple a day keeps (the doctor)/(doctors) away? An apple a day keeps the doctor away An apple a day keeps the doctor away. 关于an apple a day,keeps the doctor away An apple a day keeps the doctor away是什么意思(四选一)