毋須明示,已經知道係件事係點;亦都同「#啞仔食雲吞」組成歇後語 (to know exactly what's going on without expressing explicitly; to know the ins and outs of sth; literally: there is a sum in one's mind; combined with #啞仔食雲吞 (aa2 zai2 sik6 wan4 tan1) to form a sandwich pun)
語句用例
你做過咩衰嘢自己心中有數啦。
nei5 zou6 gwo3 me1 seoi1 je5 zi6 gei2 sam1 zung1 jau5 sou3 laa1.
You know exactly what evils you've done.