FarfromthelandofAntarctica(南极洲)ahugeshelfoficemeetstheocean.AttheundersideoftheshelftherelivesasmallfishtheAntarcticcod.

Forfortyyearsscientistshavebeencuriousaboutthatfish.Howdoesitlivewheremostfishwouldfreezetodeath?Itmusthavesomesecret.TheAntarcticisnotacomfortableplacetoworkandresearchhasbeenslow.Nowitseemswehaveananswer.

Researchwasbegunbycuttingholesintheiceandcatchingthefish.Scientistsstudiedthefish’sbloodandmeasureditsfreezingpoint.

Thefishweretakenfromseawaterthathadatemperatureof-1.88℃andmanytinypiecesoficefloatinginit.Thebloodofthefishdidnotbegintofreezeuntilitstemperaturewasloweredto-2.05℃.Thatsmalldifferenceisenoughforthefishtoliveatthefreezingtemperatureoftheice-saltmixture.

Thescientists’nextresearchjobwasclear:Findoutwhatinthefish’sbloodkeptitfromfreezing.Theirsearchledtosomereallystrangethingmadeupofaprotein(蛋白质)neverbeforeseeninthebloodofafish.Whenitwasremovedthebloodfrozeatseawatertemperature.Whenitwasputbackthebloodagainhaditsantifreezequalityandaloweredfreezingpoint.

Studyshowedthatitisanunusualkindofprotein.Ithasmanysmallsugarmolecules(分子)heldinspecialpositionswithineachbigproteinmolecule.Becauseofitssugarcontent.Itiscalledaglycoprotein.Soithascometobecalledtheantifreezefishglycoprotein.OrAFGP.

1.Whatisthetextmainlyabout?

A.TheterribleconditionsintheAntarctic.

B.Aspecialfishlivinginfreezingwaters.

C.TheiceshelfaroundAntarctica.

D.ProtectionoftheAntarcticcod.

2.WhycantheAntarcticcodliveatthefreezingtemperature?

A.Theseawaterhasatemperatureof-1.88℃.

B.Itlovestoliveintheice-saltmixture.

C.Aspecialproteinkeepsitfromfreezing.

D.Itsbloodhasatemperaturelowerthan-2.05℃.

3.Whatdoestheunderlinedword“it”inParagraph5referto?

A.Atypeofice-saltmixture. B.Anewlyfoundprotein.

C.Fishblood. D.Sugarmolecule.

4.Whatdoes“glycol-”intheunderlinedword“glycoprotein”inthelast