on the alert

基本解释

Often on the alert, she checks once but twice in the event...
她总是警惕着，一个事情上检查了一遍又一遍。
He whose expectation does not lead him to be on the alert for its coming will get but little.
所以一个人的期待，倘使不能警觉到神助之将临，所得必属稀少。
We are therefore campaigning for authors, researchers and editors to be on the alert for plagiarism and to work against cultural misunderstandings.
因此我们正在帮助论文作者、研究人员以及杂志编辑小心提防剽窃，而且还要对抗文化上的误解。

For the first time the W.H.O.raised its alert level from phase four to phase five on April twenty-ninth.
because all we konw now it's orange alert, the alert level has gone up or gone down We don't really know what it goes on behind the scene.
我们都知道现在是橙色警报，警戒线时高时低,我们真的不知道,事情背后是如何处理的。
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But it has taken on new urgency,coming one day after the World Health Organization raised its global swine flu alert to Phase 4 on the six-point scale.

He said he had warned all his employees to be constantly on the alert.
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