But,they warn that persons with weakened defenses for fighting disease are at greater risk.

VOA: special.2009.10.13

So I should warn the people sitting at the back that my handwriting is pretty bad, that's one reason for moving forward.

提醒一下坐在后面的人,我的板书写得很糟,所以最好往前坐

耶鲁公开课 - 博弈论课程节选

I should also warn you that this code includes some Python concepts, at least one, that you have not yet seen.

我得事先说明这个代码中,包括了一些你没见过的Python语言的概念，至少一个。

麻省理工公开课 - 计算机科学及编程导论课程节选

Monday afternoon, Thai soldiers fired shots in the air to warn off protesters throwing stones, boards and water bottles at firefighters.

VOA: standard.2009.04.13

However,both organizations also warn patients to make sure they choose certified doctors and surgeons at health care institutions that have met high standards of accreditation.

VOA: standard.2010.04.08