战国期间(公元前5世纪- 221年)，齐、燕、赵修建大量城墙保卫其边境。
During the Warring states Period (5th century BC-221 BC), the states of Qi, Yan and Zhao all constructed extensive fortifications to defend their own borders.
在从公元前5世纪至公元前221年的战国时期，秦、魏、赵、齐和燕各国建立广泛的防御工事来保卫自己的边界。
During the Warring states Period from the 5th century BC to 221 BC, the states of Qin, Wei, Zhao, Qi and Yan all constructed extensive fortifications to defend their own borders.
作者：罗炎光，刘杰雄，赖燕萍，何锦军【摘要】 目的：了解乡村人群心肺复苏（CPR）知识的的现状，探讨推广普及2005年新的CPR知识在院前急救的最佳模式。
Objective: To understand present situation of cardiopulmonary resuscitation (CPR) knowledge popularization in rural medical staff, and to explore the best way to popularize new CPR knowledge in 2005.
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