铁打的衙门，流水的官
tiě dǎ de yá men , liú shuǐ de guān
lit. the yamen is strong as iron, the officials flow like water (idiom)
fig. government officials come and go
铁
tiě
iron (metal)
打
dǎ
a semantically light, transitive verb that is combined with various grammatical objects to form compound verbs and verb-object phrases with a diverse range of meanings (e.g. 打傘|打伞[da3 san3] "to hold an umbrella", 打電話|打电话[da3 dian4 hua4] "to make a phone call", 打針|打针[da3 zhen1] "to get an injection", 打手套[da3 shou3 tao4] "to knit gloves", 打氣|打气[da3 qi4] "to inflate")
的
de
of; ~'s (possessive particle)
衙
yá
office
门
men
gate
，
,
流
liú
to flow
水
shuǐ
water
的
de
of; ~'s (possessive particle)
官
guān
government official