1、表示开头 It's said that... 据说…As we all know that...我们都知道…It's well known that... 众所周知...As/So far as I know...据我所知...It is clear/obvious that…是显而易见的 2、表示第一 In the first place 首先,从一开始First and foremost 首要的;第一To begin with 首先,起初The most important factor that we have to take into consideration is ...我们必须考虑的最重要的因素是...