Be sure to double-check the alarm system. 再次确认一下警报系统。

　　I need you to double-check my meeting this afternoon. 我要你再次确认今天下午的会议。

　　I'll be sure to double-check everything from now on. 我从现在开始会再三确认所有事情的。

　　Let's double check. 我们再检查检查。

　　I think there's something wrong on the account.  我觉得那个账号出了点问题。

　　Let me double check. Just a moment.  我再次确认一下吧，稍等片刻。