2018届高考英语大一轮复习 unit 3 under the sea课时规范训练 新人教版选修7

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1、Unit3UndertheseaⅠ.阅读理解A(2017·四川成都诊断)Fromsleepingstandinguptoshuttingdownhalfoftheirbrain，animalshavesomestrangesleepinghabits.Nowsomeoftheseunusualhabits,fromnappinggiraffestobirdsthatsleepwhileflying,havebeenshowninachart.Thischartshowsthatlittlebrownbatsareverylethargic,_sle

2、epingforaround19.5hoursperday.Thislongperiodofsleepisthoughttobeawayofconservingenergyanditmeansbrownbatsonlyhuntforafewhourseachnightwhentheirinsectfoodisavailable.Incontrast,giraffescangoweekswithoutsleepbecausetheselargeandslowmovinganimalsareconstantlyeasytotheattacksfromp

3、redators.However,otheranimalsareexpertsatmultitaskingandcanswimorflywhilesleeping.Forexample,dolphinsandwhalessleepwhilekeepinghalfoftheirbrainalert(警觉),sotheydon'tdrown,withdolphinstypicallynappingforaround10hoursaday.Themethodisknownas“logging”andithasbeenobservedinbottlenos

4、edolphins,whichkeephalfoftheirbrainatalowlevelofalertness.Thisallowsthedolphintokeepenoughconsciousnesstocarryonbreathingthroughitsblowhole.Whileseaottersaren'talertwhiletheysleep,theyformraftssotheyarenotseparatedfromeachother.Thecreaturessometimesholdhandsorpawswhentheysleep

5、andtypicallyeat,sleepandrestwhilefloatingingroupsofrafts.1．Theunderlinedword“lethargic”inParagraph2isclosestinmeaningto________.A．sleepy　　　　　　　　　　　B．inactiveC．energeticD．movable2．Whydolittlebrownbatshavealongperiodofsleep?A．Toavoidsunshine.B．Tosavemoreenergy.C．Torelaxthemselve

6、s.D．Towaitfortheirinsectfood.3．Howdodolphinsavoiddrowningwhilesleeping?A．Bytakingextranaps.B．Byholdinghandsorpaws.C．Bykeepinghalfoftheirbrainalert.D．Bybreathingthroughtheirblowholes.4．Whatdoseaottersdoinordernottobeseparatedfromeachother?A．Theydon'tsleep.B．Theyfloatonrafts.C．T

7、heyfloatingroups.D．Theyholdhandsallthetime.【语篇导读】　文章介绍了小棕蝠、长颈鹿、海豚、鲸和海獭等动物特殊的睡眠习惯。1．解析：选A。词义猜测题。根据画线词后的sleepingforaround19.5hoursperday可知，小棕蝠每天大部分时间都在睡觉，由此可推断lethargic在此表示“昏昏欲睡的”，与sleepy意义相近。inactive意为“不活动的；怠惰的”；energetic意为“精力充沛的”；movable意为“活动的”。2．解析：选B。细节理解题。根据第三段前半句Thislongpe

8、riodofsleepisthoughttobeawayofconservingenergy...可知，小棕蝠睡得多是因为