2020+2022英语周报八年级十四期答案

18.【命题意图】本题考查一元二次不等式，主要考查三个二次之间的关系以及分类讨论等思想，是中等题【解析】(1)不等式ax2+bx+3<2x的解集为(-∞，-1)U(3,+o)即方程ax2+(亿-2)x+3=0的两根为x=-1,x2=3.….2分-1+3=b-2a由韦达定理得：分-1x3=3解之得，Q=-1,b=4.….6分(2)由(1)可知，令f(x)=-x2+2x+3,对称轴方程为x=1,所以f(x)在x∈[m,1]上单调递增，…9分m2-2m-2≤0所以当x=m时，f(x)=-m2+2m+3≥1，即m<1所以m∈[1-√3,1)12分

第二节书面表达（满分25分）One possible version:Dear Harry.I am glad to tell you about the study tour organized by our school last Sunday.We set off by coach early in the morning and arrived at a big farm in the suburbs at 10,00 am.There wesaw the farmers busy harvesting their crops and fruits with machines.You can imagine how happy we werewhen we were invited to taste the fresh apples and grapes.After that.we headed for a folk art muscumnearby.It collected many pieces of furniture and farming tools from the old days.We couldn't help admiringthe great wisdom of the ancient Chinese people.I think the study tour is really rewarding.It has taught us a lot about farming and our rural culture.All the best wishes.Yours sincerely.Li Hua

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