英语周报答案2021-2022七年级上册期末答案

19.【命题意图】本题考查线面垂直及线面角，要求学生掌握线面垂直的证明及利用空间向量求空间角的方法【解题分析】(1)如图，取BC的中点G,连接DG,FG,EG.…·1分.BF=CF=√2，BC=2,.FG⊥BC,且FG=1,平面FBC⊥平面ABCD,∴.FG⊥平面ABCD,…2分又.ED⊥平面ABCD,∴.FG∥ED.…3分DL:---.四边形ABCD是菱形，∠DAB=60°，AB=2,.DG⊥BC,且DG=√3，DF平面BCE,.DFEG,…4分在直角梯形ErGD中，△DFGn△BGD,瓷-SDE=3.…6分(2)设AC∩BD=O,如图所示，建立空间直角坐标系O一xy必∠DAB=60°，AB=2,AC=23,BD=2,Aw50.0B01.0).E0.-1,3)F-9号。…8分设平面EAB的法向量为n=(x,y,z),AB=(-√3,1,0)，BE=(0,-2,3),F=3In·AB=0-√3x十y=0令y=3,则n=(W3,3,2),……10分1oasn迹=-瓷，11分故直线EF与平面AEB所成角的正弦值为名.12分

第二节(满分25分)One possible versionThen came the Rajasthan /v trip which was our official last trip I hanged out with my otherErieiends while she with the other two girls. I wasn,t enjoying this trip at all, which she could makeBout. When she saw me approaching the common washroom, she followed me in and shut thedoor. I didn 't know how to react. She gave me a tight hug and broke down. My tears were alsoout of control We knew we both wanted to be in each others company. We promised to growmature and let it not affect our friendshipaozIt's been almost 7 years after graduation since we picked up our friendship. Shes one of thefew people I really count on in my life. She's been with me through all my struggles, helping meconstantly to grow into a better individual. So have I. The only learning from our relationshipis-if someone is meant to be in your life, they will ensure they stay around some way or theher Willingness to keep a relationship should come from both the sides

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