for a certainty造句

1、I know for a certainty that the company has been bought up.
我确实知道公司已经被人收购了。

2、I know for a certainty that he will be here in time.
我肯定他会准时到这里来的。

3、I know for a certainty that the company has been bought up
我确实知道公司已经被人收购了。

4、I know for a certainty that he will be here in time
我肯定他会准时到这里来的。

for a certainty翻译