下学期Unit16thesea高二英语课件
日期：2010-07-03 07:36
Seenfromspace，theearthlooksblueTwothirdsoftheearth’ssurfaceismadeupofvastoceansPartOneTheSea1Charactersofthesea(1)Vastandblue(2)saltycontains35partsofsaltperthousandpartsofwater----35%byweight11othermineralsmakeupthewater(3)cleanSeaweedsproducevariouschemicals2TheMediterranean(1)longmorethan3700km(2)wide1800kmatitswidestpoint(3)warmcanreachupto25°Coreven29°C(4)salty37and39partsofsaltperthousand37%and39%byweightTheMediterraneanQuestion:Whydoesittake80yearsforMediterraneanwatertobechangedwithAtlanticwater?OnlyonenarrowentranceTheAtlantic3coralbedsCoralisnotaplantbutavarietyofanimallifeofdifferentshapesandbrightcolorsCertainconditionsforcoraltolive(1)Watertemperatureabove20°C(2)Plentyoflight(3)Clearwater(4)Depthoflessthan60metersLet’slookatbeautifulcoralThelongestcoralbedintheworldItliesoffthenortheastcoastofAustralia，about2010kilometerslongParttwoSaltlakes1theGreatSaltLake---thesaltiestlake，27%，
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