The World Health Organization says it needs to see clear evidence of sustained community transmission of the swine flu virus from person-to-person in at least two regions of the world before it raises its alert to the phase six pandemic level.

VOA: standard.2009.05.14

This is more of a spoiler alert, but you've had 41 years to see this movie.

它不只是一个扰流警报，但是你用了41年来看这个电影。

哈佛公开课 - 计算机科学课程节选

Because it's a very intense job they have to be alert every moment.

因为是高度集中的工作,他们需要时刻保持警惕。

普林斯顿公开课 - 国际座谈会课程节选

For the first time the W.H.O.raised its alert level from phase four to phase five on April twenty-ninth.

VOA: special.2009.05.06

In case any of you would like to get involved in research there are very often colleagues of mine or graduate students who are doing interesting projects who will ask me to alert you to the possibilities of working with them.

如果你们希望参与研究,我的同事和我带的研究生,正在做一些很有意思的项目,他们会让我把这些信息告知你们

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

He strained his eyes to see he knew not what. His senses were all alert.

VOA: special.2009.10.31

Pyongyang also promised to alert the South if similar situations arise in the future.

VOA: standard.2009.09.09

The U.S.State Department has issued a fresh travel alert for India, saying the U.S.government continues to receive information that terrorist groups may be planning attacks here.

VOA: standard.2009.10.30

"With that,I expect the security agencies to be 24-hours alert.

VOA: standard.2009.07.30

General Fonseka,in the letter, says Sri Lanka asked India on October 15 to place troops on alert in case they would be needed to intervene to foil a coup on the island.

VOA: standard.2009.11.14

"I hope that what a study like this will do would be to help alert clinicians, residents in training, and medical students that severity is an important factor to consider in planning treatment,".

VOA: standard.2010.01.08

"It's physiological and it's emotional." "Physiologically,we have a tendency when we come into a situation that seems dangerous we get a lot of chemicals flowing through our bodies to help us stay alert, to be able to act if we need to act.

VOA: standard.2010.07.01

"This change to a higher phase of alert is a signal to governments, to ministries of health and other ministries, to the pharmaceutical industry and the business community that certain actions should now be undertaken with increased urgency, and at an accelerated pace,"

VOA: standard.2009.04.29