Manual machines can put pearls in any place in the outer zone.

手动机器人可以把珍珠放在外区任何地方。

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The outer zone is made up of reticular cells, columnar cells and mucous cells;

外区主要由网状上皮细胞、柱状上皮细胞、黏液细胞组成；

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Home Office officials have said in the event of an attack, the area immediately surrounding the scene, known as the "hot zone", would have an inner and outer cordon, with mobile shower units.

BBC: Warning over chemical attack 'cordon'