there is no strick rule on this

來源: 於 2011-06-09 11:20:23 [博客] [舊帖] [給我悄悄話] 本文已被閱讀：次

it is all based on the rule developed in many years. If you are not grow up in Beijing then do not try to copy those ... It is a culture and you just have to respect it ...