certain形容詞表語形式

往往用於It is certain that…句式中，例如：

1、It is certain that Rodney arrived the previous day.羅德尼肯定是頭天到的。

2、Their seating arrangements are unknown ， but it is certain that they were arranged in a certain order.其座次的順序尚不得而知，但肯定是有區別的。