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Bacteria(细菌)areextremelysmalllivingthings.Whilewemeasureourownsizesininchesorcentimeters,bacterialsizeismeasuredinmicron.Onemicronisathousandthofamillimeter;apinheadisaboutamillimeteracross,Rod-shapedba
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Bacteria(细菌)areextremelysmalllivingthings.Whilewemeasureourownsizesininchesorcentimeters,bacterialsizeismeasuredinmicron.Onemicronisathousandthofamillimeter;apinheadisaboutamillimeteracross,Rod-shapedbacteriaareusuallyfromtwotofourmicronslong,whileroundedonesaregenerallyonemicronacross.Thus,ifyoumagnifiedaroundedbacteriumathousandtimes,itwouldbejustthesizeofapinhead,whileagrown-uphumanenlargedbythesameamountwouldbeoveramiletall.

Evenwithanordinarymicroscope(显微镜),youmustlookcloselytoseebacteria.Usingamagnificationof100times,onecanhardlyfindbacteria.Norcanonemakeoutanythingoftheirstructure(结构),ofcourse.Onlybyusingspecialcolors,canoneseethatsomebacteriahavewavy-looking“hairs”calledflagella.Othershaveonlyoneflagellum.Theflagellamoveroundacentralpoint,pushingthebacteriathroughthewater.Manybacterialackflagellaandcannotmoveaboutbytheirownpower,whileotherscanmovealongoversurfacebysomelittle-understood“machinery”.

Fromthebacterialpointofview,theworldisaverydifferentplacefromwhatitistohumans.Toabacterium,waterisasthickasmolasses(糖浆)istous.Bacteriaaresosmallthattheyareaffectedbythemovementsofthechemicalmolecules(分子)aroundthem.Bacteriaundermicroscopes,eventhosewithnoflagella,oftenjumpupanddowninthewater.Thisisbecausetheyknockwiththewatermoleculesandarepushedthiswayandthat.

36.Theunderlinedwordmagnifiedmeans_______________.

A.enlarged B.widened

C.killed &n

隋清回答:
  小题1:A小题2:B小题3:C小题4:A小题5:A   略
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