Everyday they work like a dog.

他们每天像狗一样工作着。

If you want to be successful, you must work like a dog.

如果你想要成功，就必须拼命工作。

They say that to be successful, a person has to work like a dog.

他们说，一个人想要成功就得拼命工作。

They say that to be successful, a person has to work like a dog. This means they have to work very hard.

他们说，为了成功，人必须像狗一样工作，意思是说，人必须非常努力地工作。

That means many people are competing for the same things, like good jobs. They say that to be successful, a person has to work like a dog.

比如一个职位，很多人都在竞争，他们说如果想成功，就得像牛(老美说像狗)一样辛勤劳作。