AremarkablevarietyofinsectsliveinthisplanetMorespeciesofinsectsexistthanallotheranimalspeciestogether.Insectshavesurvivedonearthformorethan300millionyears,andmaypossesstheabilitytosurviveformillionsmore.
Insectscanbefoundalmosteverywhere--onthehighestmountainsandonthebottomofrushingstreams,inthecoldSouthPoleandinbubblinghotsprings.Theydigthroughtheground,jumpandsinginthetrees,andrunanddanceintheair.Theycomeinmanydifferentcolorsandvariousshapes.Insectsareextremelyusefultohumans,pollinating(授粉)ourcropsaswellasflowersinmeadows,forests,desertsandotherareas.Butlicksandsomeinsects,suchasmosquitoesandfleas,cantransmitdisease.
Therearemanyreasonswhyinsectsaresosuccessfulatsurviving.Theiramazingabilitytoadaptpermitsthemtoliveinextremerangesoftemperaturesandenvironments.Theoneplacetheyhavenotyetbeenfoundtoanymajorextentisintheopenoceans.Insectscansurviveonawiderange,ofnaturalandartificialfoods—paint,pepper,glue,books,grain,cotton，otherinsects,plantsandanimalsBecausetheyaresmalltheycanhideintinyspaces.
Astrong,hardbutflexibleshellcoverstheirsoftorgansandisresistanttochemicals,waterandphysicalimpact.Theirwingsgivethemtheoptionofflyingawayfromdangeroussituationsortowardfoodormales.Also,insectshaveanenormousreproductivecapacity:AnAfricanantqueencanlayasmanyas43,000eggsaday.
Anotherreasonfortheirsuccessisthestrategyofprotectivecolor.Aninsectmayberightbeforeoureyes,butnearlyinvisiblebecauseitiscleverlydisguisedlikeagreenleaf,lumpofbrownsoil,graylichen(青苔),aseedorsomeothernaturalobjectSomeinsectsusebright,boldcolorstosendwarningsignalsthattheytastebad,stingorarepoison.Othershavewingpatternsthatlookliketheeyesofahugepredator,bitter-tastinginsects;hungryenemiesarefooledintoavoidingthem.
练习题：
Choosecorrectanswerstothequestion:
1.InsectscanbefoundinlargeamountsinthefollowingplacesEXCEPT_____.
A.onthemountainswithlittleair
2.Insectsprotectthemselvesfromchemicalsby_______
C.flyingawaywhennecessary
3.Someinsectsdisguiselikenaturalobjectssoasto______
A.frightenawaytheirenemies
4.Thepassagementionsthatinsects______.
A.canbefoundinanyextremeenvironments
B.havesurvivedlongerthananyothercreatures
C.canbefedonanynaturalorman-madefoods
D.areimportantforthegrowthofcropsandflowers
5.Thepassageismainlyabout______
A.howinsectssurviveindifferentplaces
B.whyinsectscansurvivesosuccessfully
C.whatinsectscandototheenvironment
D.whereinsectscanbefoundinquantity
1.[D]事实细节题。本题考查对复合句的理解。本题涉及两个段落，第2段及第3段都提及昆虫大量生长的地方，第3段第3句中的Theoneplace指出了答案。
2.[B]事实细节题。本题考查对复杂句的理解。第4段第1句指出了答案。protect…from…是对resistantto的同义替换。
3.[B]推理判断题。本题考查对长句的理解。最后一段第2句中的nearlyinvisible表明昆虫伪装是为了不被发现，因此B为正确选项。其他选项虽然都是昆虫伪装的目的，但都与伪装成自然物体无关。
4.[D]推理判断题。本题考查对含有分词结构句子的理解。根据第2段倒数第2句中的useful及分词结构pollinating可推断昆虫对植物的生长有益处。选项A、B、C中都有any,过于绝对。由第3段第2、3句可知选项A不对。文章虽在开头指出昆虫存活的年代久远，但全文未提到它是存活时间最长的生物，所以选项B错误。至于昆虫的食物，第3段倒数第2句有提及,但只是awiderangeof,由此可排除选项C。
5.[B]主旨大意题。本文前两段首先描述了昆虫生存了很长的时间，并能在各种地方生长，然后引出文章要讨论的重点，即昆虫为什么能成功存活。第3段第1句为本文的中心句，因此本题正确选项为B。
U633687664
U582121265
