2018-2022 英语周报 高二 05答案

23.解:(1)法一:由a+b=4得a+b4 a b当且仅当“即a=b=2时等号成立1+1的最小值为1法二:∵a>0,b>0,a+b=4a+b5考倒计时微博与新以即a=b=2时等号成又a+b=4,进而得≥1,故一+一的最小值为1当且仅当“a=b=2”时等号成立其它解法相应给分(2)法一:由2(a2+b2)≥(a+b)a+b+8分由(1)知进而得:(a+1+(6+1)1≥1(a+b+1+1)≥25当且仅当“a=b=2”时等号成立10分法二由2(+6)=(a+6)得:a2+62≥18a+-+4当且仅当“a=b=2”时等号域法三:由柯西小等式b

【篇章导读】这是一篇说明文,研究者发现,大象,山羊,牛等的排泄物里含有大量纤维素,可以用来造纸,比用木头造纸更经济,而且原料充足。32.C【解析】考查段落大意。本段第一句为主题句,主要讲述了用动物排泄物造纸这一想法的产故选C33.D【解析】考查细节理解,根穆段中“ Elephant, horse and caktes could bendless sources for a key elertrent needed to makepaper.”以及第三段中“Upto40 percent of thosewastes are cellulose, which is easily accessible.Therefore, making paper from the partiallydigested material would take much less energythan using raw wood. Additionally, it wouldrequire fewer chemical treatments."可知,纤维素是造纸必需的元素,而动物粪便里含有40%的纤维素,由此判断,D选项符合题意34.B【解析】考查细节理解。根据第三段中Therefore, making paper from the partiallydigested material would take much less energythan using raw wood.”可知,用动物的排泄物造纸可以比用木头造纸节省能源。故选B35.A【解析】考查词义猜测。根据最后一段中Using wastes, we can reduce the number ofsteps needed in papermaking, simply because theanimal alreadylhewedthe plan”可知,用动物排泄物造纸富了适纸必需的一些过程:再根据上段中 Bat it requires little because there is noeed to break it down into small parts for use inpaper”可知,省却的这个过程就是将原料粉碎的过程,也就是动物胃里的食物是经过咀嚼和用胃酸浸泡和腐蚀过的。由此推知划线部分的意义接近“处理”,故选A。

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