日积月累 (rì jī yuè lěi)

to accumulate over a long period of time

Character breakdown

Usage

词汇要靠日积月累,不能一蹴而就。

Vocabulary depends on daily accumulation; it can't be done overnight.

Cíhuì yào kào rìjīyuèlěi, bù néng yīcùérjiù.