1
rat on sb/sth
rat on 是固定搭配，on 后接被背叛、背弃或告发的人、团体或事业；若要说明向谁告发，后面可用 to the police 等。
He ratted on his teammates.
他出卖了自己的队友。
告发；检举；出卖
ratted — past of rat
先理解核心含义，再看它在真实句子里的用法。
告发；检举；出卖
To inform on someone; to betray someone to the police or authorities.
He ratted on his teammates.
他出卖了自己的队友。
猎杀或杀死老鼠
To hunt or kill rats.
该死的；用于咒骂中
Damn, drat, blast; used in oaths.
背叛政党、事业或原则；背叛某人,抛弃某人或事物
To betray a political party, cause or principle; to betray someone, to desert a person or thing.
告发某人；向警方或当局出卖某人
To inform on someone; to betray someone to the police or authorities.
rat
Base
原形
rats
3rd person
第三人称单数
ratting
-ing
现在分词
ratted
Past
过去式
ratted
Past participle
过去分词
He rats on his colleagues to the boss.
他向老板告发同事。
She ratted on her friend yesterday.
她昨天背叛了朋友。
They have ratted on the agreement.
他们已经违背了协议。
规则动词，注意加-ed/-ing时双写t。
He ratted on his boss to get a promotion.
他为了升职告发了他的老板。
The criminal ratted out his gang members to reduce his sentence.
罪犯供出了他的帮派成员以减轻刑罚。
If you rat on us, we'll never trust you again.
如果你出卖我们，我们再也不会相信你。
rat on 是固定搭配，on 后接被背叛、背弃或告发的人、团体或事业；若要说明向谁告发，后面可用 to the police 等。
He ratted on his teammates.
他出卖了自己的队友。
go + 动词-ing 表示外出进行该活动；ratting 是 rat 的现在分词，专指猎鼠活动。
They went ratting in the old barn.
他们去旧谷仓捕鼠。
Not this
He ratted his boss to the police.
Use this
He ratted on his boss to the police.
rat 表示“告发/出卖某人”时是不及物动词，必须用 rat on somebody 结构，不能像汉语“出卖某人”那样直接接宾语；on 后接被告发的人，to 后接警方等受理方。
Not this
He rat on me yesterday, so I got punished.
Use this
He ratted on me yesterday, so I got punished.
rat 是规则动词，过去式需双写词尾 t 再加 -ed 成为 ratted；表示过去发生的事不能用动词原形 rat。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
背叛某人；出卖某人
He ratted on his friends to save himself.
他出卖朋友以求自保。
告发某人；检举某人
Someone ratted us out to the police.
有人向警方告发了我们。
捕鼠；猎鼠
Farmers used to go ratting with dogs and traps.
农民过去常带着狗和捕鼠夹去捕鼠。
告发；出卖
He ratted on his colleagues to get a promotion.
他为了升职而告发了同事。
告发；背叛
The thief ratted out his partner in crime to the police.
窃贼向警方告发了他的犯罪同伙。
永远不要出卖你的朋友，并且管住自己的嘴。
Henry Hill's motto in Goodfellas is 'Never rat on your friends and always keep your mouth shut.'
《好家伙》中亨利·希尔的座右铭是：‘永远不要出卖你的朋友，并且管住自己的嘴。’
Use ratted naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
rat 作动词是“告发/背叛”，想象大老鼠偷偷溜走、出卖同伴：rat 这个词里有个 at（指向），像在指认目标，帮你记住背叛之意。
语域：mixed 常见场景：everyday informal talk、school or workplace disputes、police informant situations、political or party conflicts、hunting or pest control rat 作动词表示“背弃、告发、出卖”时通常用于非正式口语，多出现在日常聊天、校园或职场冲突等场景；表示“捕鼠”时则较中性，多与打猎或除害相关。正式书面语中应慎用非正式义项。
及物动词表示‘弄蓬松’，不及物动词表示‘捕鼠’或‘变节’
Dictionary facts from DICTIONARY_API_DEV, ECDICT, WIKTIONARY, WORDNET.