1 How long can a human being go (ie survive) without food?
2Although the Negroes were humanbeings just like the whites they were not treated as humanbeings.
後面指的是生物體 也是可數的
1 Are you quite sure there is no living beings on Mars?
2 (linguistics) belonging to the class of nouns that denote livingbeings.
如果不確定可以查閱朗文詞典online /
和劍橋詞典 http://dictionary.cambridge.org/