I Iearned extra credit snitching on kids who were smoking behind the equipment shed.

我靠着举报有学生躲在器具室后面抽烟得到了额外学分。

But ratting someone out or snitching on them can be for any age.

但“rat someone out（出卖某人）”或是“snitch on them（告发某人）”适用于任何年龄段。

About how you snitched on me to Carlos? No, thanks. I'm all caught up on that.

谈你怎么向卡洛斯告我的密？不，谢了。我已经都知道了。

A rat snitches on someone to an authority figure – a parent, a teacher, a police officer.

告密的人会向有权威的人告发某人，如向父母、老师、警察告密。

They refused to take any accountability, blaming the co-worker who snitched on them.

他们拒绝承担任何责任，并指责告密他们的同事。

The prisoner's dilemma is a game where two criminals are caught and are independently interrogated, and have to choose whether they snitch on the other one or not.

在“囚徒困境”游戏中，两个被抓的罪犯要被单独询问，他们得去选择要不要告发另一个人。

This is a classical scenario in game theory where two convicted criminals are pondering whether they should snitch on each other without knowing how the other decided to act.

这是博弈论中的经典场景，两个被定罪的罪犯考虑他们是否应该在不知道对方的决定的情况下告发对方。

So, calling someone a " rat" is never an expression of respect or affection. When describing people, a " rat" is someone who is not loyal or cannot be trusted. A rat snitches on someone to an authority figure – a parent, a teacher, a police officer.

所以，称某人为" rat" （背叛者）从来都不是一种尊重他人或充满情感的表达。在描述人的时候，" rat" 是指不忠诚或不可信的人。上位者经常告密如向家长，老师或警察。