发愤忘食 [- - wànɡ shí]study [work] hard, neglecting one's meals; be so immersed in work as to forget one's meals; be roused to such diligence as to forget one's meals; One studied with such eagerness that he forgot his meals.; work so hard as to forget to eat [neglect one's meals]：
•¶ 有的学生有时候甚至发愤忘食。 Some of the students were so immersed in their studies that they sometimes even forgot their meals.