1、as American as apple pie – This means that something has qualities, or features, that are typical of the United States or the people of the United States.
as American as apple pie: 具有典型的美国或美国人的特征。
Example: My brother drives a Ford truck and wears blue jeans every day; he is as American as apple pie.
2、an apple a day keeps the doctor away – Apples are considered a nutritious food; so this expression is intended as advice. To stay healthy (and to not have to visit the doctor) you should eat healthy food like, an apple, every day.
an apple a day keeps the doctor away: 苹果富含营养，所以这种表达代表一种建议。要保持健康(不用看医生)你应该每天吃苹果这样的健康食物。
Example: Whenever I get sick my mother always reminds me to take care of myself by saying, “An apple a day keeps the doctor away.”
3、the apple of my eye – This is a way of referring to a favorite, or beloved, person.
the apple of my eye：指代一个喜欢或所爱的人。
Example: My daughter is the apple of my eye; she makes me happy every day.
4、(like) comparing apples and oranges – This expression is used when someone is talking about two non-similar items, but trying to compare them as though they were similar.
(like) comparing apples and oranges: 当某个人在讨论两个不相同的事物，但又试图把它们像相同的事物一样进行比较，可以使用这种表达。
Example: You can’t compare who works harder, me or you; I am a teacher and you are a fisherman, and that is like comparing apples and oranges.
one rotten apple spoils the whole barrel – This expression means that one bad person influences everyone around him or her and can make them act bad too.
5、one rotten apple spoils the whole barrel: 一个坏人可以对他身边的每个人产生坏的影响，会让周围的人做出不好的行为。
Example: Jimmy is the rotten apple that spoils the barrel in my class, I wish I didn’t have to be his teacher all year.
6、How about them apples? or How do you like them apples? This question is the same as ‘What do you think of that?’ Asking this question is usually a way of bragging or showing off.
How about them apples? or how do you like them apples?: 意思等同于‘what do you think of that?' 问这个问题通常在自夸或炫耀。
Example: I was picked to join the basketball team and you weren’t. How do you like them apples?