A young idler, an old beggar. 少壮不努力，老大徒伤悲。
Bad news has wings. 好事不出门，坏事传千里。
Between friends all is common.
朋友之间不分彼此。
Caution is the parent of safety. 小心驶得万年船。
Constant dripping wears away a stone. 水滴石穿，绳锯木断。
Do as the Romans do. 入乡随俗。