Number one 自己

【例句】
They are always looking out for number one and taking care of number one.
他们一直是先为自己着想，照顾自己的利益。

They are always looking out for number one and taking care of number one. It is as if they are the one and only person on Earth.
他们总是先为自己着想，只关心自己的利益，就好像他们是地球上唯一的人。