They earn a living(by)doing housework for other families.

他们为别的家庭做家务来谋生计。

Lawyers earn a living by the sweat of their browbeating .

律师以吹胡子瞪眼维持生计。

Earn a living by Under his instruction I have made great progress in English.

在他的教导下，我的英语有了很大进步。