是賓語從句，例如:

1.We can never be certain that a verification system is correct either.我們不可以肯定證明系統是正確的二者之一。

2.See we need to be certain that we're comparing things that are like.我們必須明確相比較的事物是同類的。

3.Be certain that money is coming to you.確定金錢向你走來。

由“Itis+adj.+that…”構成的主語從句。
Itiscertainthatweshallbelate.我們肯定要遲到了。
It’sstrangethathedidn’tcomeyesterday.真奇怪他昨天沒來。

例句與用法：

He was certain that his house had been nudged off its foundations 他斷定他的房子已經偏離了地基。

How can we be certain that the chosen assignment is the right one ?我們又怎樣才能確信所選擇的賦值是正確的呢？

But I was certain that we would not have to wait long for a chilly blast from moscow .但我斷定，要不了多久，莫斯科就會刮來一股冷風。

I would feel the red rising in my face. I was certain that everyone was looking at me .我只覺得自己的臉越來越紅。我相信大家都在看著我。