发愤研究学问，常常忘记吃饭，一旦有所收获便又高兴地忘记了忧愁，连自己的渐趋衰老也没有感觉到。
I do not know what I may appear to the world， but to myself I seem to have been only like a boy playing on the sea-shore， and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary， whilst the great ocean of truth lay all undiscovered before me.
"The value of a thought lies in its functional efficacy."
