The antibodies indicate that the body's immune system has tried to defend itself against the virus, a sign of prior exposure or infection.

抗体就是指人体的免疫系统已经努力抵抗病毒了，是一种提前暴露于病毒之中或感染的迹象。

youdao

Once the reader has reached his or her "limit" - let's say 10 or 12 stories - the reader will be prompted to sign into the site as a paid user. the Financial Times USES a similar system.

一旦他们达到上限——比如十篇或十二篇，该读者将被要求以付费用户身份登入网站(《金融时报》就采用了类似的系统)。

youdao

Members of the group were born deaf and never learned Spanish or a formal sign language, but they have developed a gesture system to communicate with people around them.

研究人群天生就是聋子，从没有学过西班牙语或其它正式的符号语言，但是他们有一套能让他们与周围人沟通的手语系统。

youdao

The third group of symptoms relates to what has been called hyperarousal, which means an emotional, mental and physical tendency to drive one's flight-or-flight nervous system too hard, a classic sign of which is a tendency to startle too easily.

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Yes, I do think it fair to say that wild gyrations are a sign of failure in an economic policy or system.

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