同等学力英语练习32

最后黄金冲刺抢分阶段

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A.imitate

B.between

C.otherwise

D.accelerate

Phrases:

A.wouldbedifficultto1

B.from2itsfeathers

C.enablingthebirdto3

D.it4could

Theemperorpenguintrapsairinitsfeathers.Notonlydoesthisinsulatethebirdagainstextremecoldbutitalsoenablesittomovetwoorthreetimesfasterthan5.How?Marinebiologistshavesuggestedthatitdoessobyreleasingtinyairbubbles6.Asthesebubblesarereleased,thereducefrictiononthesurfaceofthepenguinswings,7.Interestingly,engineershavebeenstudyingwaystomakeshipsgofasterbyusingbubblestoreducefrictionagainsttheirhulls(船身).However,researchersacknowledgethatfurtherinvestigationischallengingbecause"the