In addition, HIV infection from 2 to 12 weeks to detect HIV from the blood of antibodies, but not before been contagious, so be alert.

另外，感染艾滋病病毒2周至12周才能从血液中检测出艾滋病抗体，但在此之前已具有传染性，所以必须高度警惕。

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Contagious yawning is thought to be an evolved mechanism for keeping groups alert so they "remain vigilant against danger," Gallup said.

呵欠传染被认为是进化出来用于保持群体的警惕性使群体“在危险面前保持警觉，”盖洛普说。

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A key advantage here is that you can alert LOB management before it's too late, so action can be taken to fix a problem.

这里的一个主要优势是，您可以在一切太晚之前向lob管理层发出警告，以便采取相应措施来修复问题。

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So, you want to be alert to the performance in January to use the strength, take some profits, and also as a sign of continued strength going forward with the stock market.

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In 1978 the Japanese government passed a law requiring adequate warnings to be given of major earthquakes so that people could be evacuated and emergency services put on full alert.

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They can also be combined with sensors so that a tagged crate of refrigerated goods could alert a system if perishable items inside became too warm, for example.

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