When we get a cold, we can see and feel our body's defence systems activating.

当我们患了感冒，我们可以观察和感觉到身体里的防卫系统开始运作。

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Medical technology: Researchers are devising laser-defence systems to shoot down mosquitoes.

医学科技：研究人员正在设计激光防卫系统用于击落蚊子。

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Analysts question whether it is as stealthy as claimed and its ability to penetrate the best future air-defence systems.

分析家们怀疑其隐身能力是否有声称的那么好、有没有能力穿透未来最好的防空系统。

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Syria, they say, has one of the most sophisticated, Russian-made air-defence systems in the world.

ECONOMIST: Foreign policy

The South Korean news agency Yonhap said that two warships equipped with Aegis defence systems would monitor the situation.

BBC: South Korea 'deploys warships to track North missiles'

The embassy in Baghdad plans to hire and manage thousands of private contractors to operate helicopters and air defence systems.

ECONOMIST: Iraq and the Pentagon