学然后知不足
verb- to learn is to know one's ignorance (the Book of Rites 禮記|礼记[Li3 ji4])
Its characters
Learn 学然后知不足 in real texts
With a free account, hover any word in the library for its meaning, hear it read aloud, save words for review timed to your memory, and see how much of each book you already know.