2022英语周报第3608期答案

18.解:(1)连接AC,因为底面ABCD为正方形,所以AC⊥BD.又因为PA⊥平面ABCD,所以PA⊥BD又AC∩PA=A,所以BD⊥平面PAC因为AEC平面PAC,所以BD⊥AE(4分)PD(2)因为PA⊥平面ABCD,所以PA⊥CD,又因为底面ABCD是边长为2的正方形,所以CD⊥AD,又PA∩AD=A,所以CD⊥平面PAD.过点E作EH∥CD,则EH⊥平面PAD,(7分)又因为PE=2EC,所以EH=4,(8分)所以Vp=AED=VE-PD≈34△ PAD X EH=XADX PA×EH=×士×2×4X(12分)

第三节书面表达wersionDear Sir or MadamMy name is Li Hua. As an exchange student fromChina, I am studying in a local school. I am reallydelighted to learn that a volunteer for your Chinese culturallic exhibition is required and I'm confident that I amtruly fit for thestart with, my advantage first lies in the fact that IChina and used to beand quite familiar with Chinese relics. Further-more, being an outgoing and optimistic boy, I am good atcommunicating with others and introducing Chinese cultureto the world is always my honor and my pleasure. Finallythere is no problem with my spoken English, as I havelived here for almost a year and I have no difficulty commu-dicating with others in EnglishI would really appreciate it if you can offer me thechance to be a volunteer in your museum. I am looking forward to your early reply.Li Hua

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