The ones that are accepted in public speech change through the years as social rules change.

VOA: special.2010.02.14

Socrates' city speech proceeds through several stages.

苏格拉底的城市论述历经几个转折。

耶鲁公开课 - 政治哲学导论课程节选

President Obama warned in a speech on Tuesday that economic pain will continue through this year and that losses of jobs and homes will not end soon.

VOA: special.2009.04.17