earn one's `keep 的意思是“挣（某人的）生活费”，这里的keep是不可数名词。例如：It's time you got a job and started earning your keep.你该去找份工作养活自己了。（摘自《朗文高级英语辞典》第5版）Now you are old enough to earn your keep. 你现在的年龄够大了，应该能自谋生计了。（摘自《外研社英汉多功能词典》）

    earn one's keep 后面加 by doing 作方式状语。例如：He earned his keep by cleaning the house. 他靠打扫房子挣饭吃。（摘自《英汉双解当代美国英语学习词典》）

earn one's keep 意思“赚取M某人生活费，值得雇用，挣饭吃，赚钱吃饭”keep

(1)vt.  保持; 保留; 遵守; 阻止;

(2)vi.  （食品）保持新; 保持健康;

(3)n.  保持，保养; 供养，抚养; 生活，生计; 饲料；牧草;

keep  n.生活费用 (英文解释：Someone's keep is the cost of food and other things that they need in their daily life.)

Ray will earn his keep on local farms while studying...  

雷求学期间会在当地的农场干活赚取生活费。

I need to give my parents money for my keep.  

我需要付给父母我的生活费。