1.To compare “apples and oranges” is to uselessly compare unlike things.

对比“不相干的事物”，没有意义。

2.The “apple of (one's) eye” is a favorite or well-like person.

掌上明珠。

3.To say that “the apple never falls far from the tree” is to suggest that a person's personality traits are close to those of the person's parents.

有其父必有其子，形容某人与父母性格相似的说法。

4.“As American as apple pie” means that something is quintessentially representative of American culture or values.

典型美式风格（苹果馅是美国的标准饭后甜食），指某事具有典型美式文化或价值观的代表性。

5.“(As) sure as God made little green apples” suggests certainty.

毫无疑问的，暗示可能性。

6.To be a “bad apple” or a “rotten apple” is to be a bad person.

坏蛋。

7.“one bad (or rotten) apple spoils the whole bunch (or barrel)” implies that one flawed element or person can undermine an effort or a group.

一条臭鱼腥了一锅汤。

8.To be “rotten to the core” is to be thoroughly bad or worthless.

坏透了，完全没价值。

9.To “polish (one's) apple” is to flatter someone; a flatterer is an “apple polisher.

阿谀奉承某人；apple polisher指马屁精。

10.To “upset the apple cart” is to ruin plans.

破坏计划。

11.A “banana republic” is a weak or corrupt country.

香蕉共和国。（指国家弱或者腐败）

12.A “second banana” is a subordinate, and the “top banana” is the leader.

Second banana是下属，top banana指领袖，领导。