習慣成自然 [ㄒㄧˊ ㄍㄨㄢˋ ㄔㄥˊ ㄗˋ ㄖㄢˊ; xi2 guan4 cheng2 zi4 ran2] habit becomes nature (idiom); get used to something and it seems inevitable second nature ◄ ►