Why would a mother's body attack her own fetus?

为什么母亲的身体要攻击自己的胎儿呢？

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If you know someone is coming up behind you to attack, turn toward the person with your hands up in front of your body and loudly say "stop" before walking away.

如果你知道有人从你后面走过来要攻击你，把手举到身前，转身大声说“停”，然后走开。

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The virus can actually destroy those white blood cells, leaving the body wide open to attack from other infections.

该病毒实际上能破坏那些白血球，使身体极易受到其他感染。

《柯林斯英汉双解大词典》

Another likely cause is a problem within the body's defenses against disease, when the defenses misunderstand signals and attack the body.

VOA: special.2009.01.06

Well, a fair definition of tickling is touching parts of the body in a mock attack.

胳肢的准确定义就是,打打闹闹时碰身体某个地方。

耶鲁公开课 - 心理学导论课程节选

A problem with adenoviruses is that your immune system recognizes them, and if your immune system recognizes the virus then it can attack the virus and eliminate it from the body.

关于腺病毒有个问题,免疫系统会识别腺病毒,如果免疫系统识别了这些病毒,就会进而攻击并从体内清除病毒

耶鲁公开课 - 生物医学工程探索课程节选

Further research into gliadin found it was made up of even smaller fragments already known to provoke cells in the body to attack the intestine.

BBC: Cause of dietary disorder uncovered

The team, from the National Cancer Institute near Washington DC, say they were able to effectively prime the "sentry cells" which alert the body to foreign attack.

BBC: 'Supercharged' immune system takes on cancer

Mr Rooney suffered multiple injuries to the head and body in the sustained attack that killed him in September last year.

BBC: John Sowden