The top and bottom sections are quite difficult to separate.顶部和底部很难分开。He's trying to embarrass you, that's the top and bottom of it.简而言之，他是想让你难堪。Leave a gap at the top and bottom so air can circulate.上下各留一个口子通风。All external doors should be bolted top and bottom.所有外面的门都应该把上下的插销全部插上。