dog eat dog 

n.殘酷激烈的競爭；損人利己的角逐；內(nèi)卷 

【解釋】

a situation of fierce competition in which people are willing to harm each other in order to succeed.

【例句】

It's dog eat dog right now at school because all the top students are competing to be valedictorian /?væl?d?k?t??ri?n/.

學(xué)校里競爭很激烈/內(nèi)卷十分嚴(yán)重，因為所有的優(yōu)等生都在競爭做畢業(yè)致辭代表（最優(yōu)秀的學(xué)生）。  

I'm afraid, in this line of work, it's a case of dog eat dog. 

恐怕在這種行業(yè)中競爭是殘酷無情的。

We're operating in a dog-eat-dog world. 

我們是在一個殘酷競爭的世界里立足。

top dog

n.（尤指競爭中的）優(yōu)勝者，奪魁者；

（某領(lǐng)域的）成功者，領(lǐng)軍人物，龍頭

【解釋】

If a person or organization is top dog, they are the most successful or powerful one in a particular group. 

【例句】

He's dying for success, and he has never concealed his ambition to be the top dog. 

他極度渴望成功，他從不掩飾他要成為領(lǐng)軍人物的雄心。

The company is the top dog in the food retail market.

這家公司是食品零售市場的龍頭。  

fight like cat(s) and dog(s)

經(jīng)常吵得很兇

水火不容

【解釋】

If two people fight like cat and dog, they frequently have violent arguments or fights with each other. 

【例句】

My brother and I were very close in age and we used to fight like cats and dogs. 

我哥哥和我年齡相仿，我們之前一直經(jīng)常爭吵不休。  

They had fought like cat and dog ever since he could remember, and he wondered how they'd managed to stay together.

從他記事起，他們就一直吵得不可開交，他不知道他們怎么還能待在一起的。 

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