一般最下面一颗不扣。不同场合扣法也不一样。社交场合扣中间的。工作场合最下面不扣其他都扣。严肃场合都扣。严肃场合不多见，表达极度尊敬的时候才用。坐下全解开，起立时候扣上。
The feature of American lifestyle can be also described with two words: Punctuality and law- abiding. Each year, tens of millions of people relocate from their home town or current residence to anothe...