Unit+4+Exploring+literature+Grammar+and+usage 高中英语译林版（2019）必修第二册

Modals情态动词Anyvisittothesouthwesternstatesshouldinclude

atriptoseetheamazingRockArtoftheprehistoricNativeAmericans.Thetermrockartreferstotwotypesofartforms-petroglyphs,whicharecarvedintotherock,andpictographs,whicharepaintedontherock.InsomeNationalParks,youdon’thavetolookfartofindmagnificentpetroglyphsbecausetheyseemtobeonalmosteveryrockorcliffface.Inotherareas,youhavetohikeuptocavesorintocanyonstoseetherockart,butitiswellworththeeffort.Regardlessofwhereyougo,yououghttobringacameratorecordthesehauntinglybeautifulimages.Usehavetotoexpressnecessity.*Inotherareas,youhaveto

hikeuptocavesorintocanyonstoseetherockart.Canyouseetherockartfromyourcar?NOWhatisnecessarytoseetherockart?Youhavetoleavethecarandhikeuptocavesorintocanyons.*Mustmorecommonlyexpressesnecessityinrules,instructions,andlegaldocuments.Usedon’thavetowhentalkingaboutlackofnecessity.Youdon’thavetolookfartofindmagnificentpetroglyphsbecausetheyseemtobeonjustabouteveryrockorcliffface.Isitnecessarytolookfar?NO.Youdon’thavetolookfar.Shouldandoughttoareusedtoexpressadvisability.YoushouldseetherockartinNewMexico.YououghttoseetherockartinNewMexico.Samemeaning?YESShouldandoughttoareusedtoexpressadvisability.YoushouldseetherockartinNewMexico.YououghttoseetherockartinNewMexico.Bothmeanit’sagoodideatoseetherockart.Practice1Writeasentenceforeachofthemodals.1.Namesomethingapersonmustdoaccordingtothelaw.2.Whatdoyouhavetodoeveryweek?3.Whatdon’tyouhavetodotonight?4.Finishthissentence:Parentsoughtto____________________5.Finishthissentence:Childrenshould_____________________RockartspansthousandsofyearsandalmostallareasoftheUnitedStatesandMexicohavesome.However,thesouthwesternstatescontainanunusuallyhighnumberofimages,ofteninoldsettlements.Asyouwalkthroughtheseareas,youmayfindfiguresofpeople,animals,orplantscarvedintotherock.Youcanalsoseeuniquegeometricpatterns.Whatwerethesepatternssupposedtorepresent?Wemayneverknow.Theartistscouldhavebeenillustratingrainorlightning.Ortheymayhavebeentryingtoshow

emotionssuchasjoyorsadness.Whateverthemeaning,itiseasytoseetheuniquenessofthisart.Usewas/weresupposedtowhentalkingaboutunknownorunfulfilledplansorexpectationsinthepast.Whatwerethesepatternssupposedtorepresent?Perhapstherockart

wassupposedto

tell

astory.Wehavenoideaofthepurposeoftheartist,sowecanonlyguess.Progressiveformofmodalsexpressapossibilityaboutsomethinginprogress,eithernoworinthepast.Theartistcouldhavebeenillustratingrain.Whendidtheartistlive?Whatweretheydoing?inthepasthavebeen

illustratingrainmodal++-ingArewecertain?No.Perhapstheywere.Practice2-Completethesentenceswiththegivenverbsandanappropriatemodal.Morethanonemodalmaybepossible.Scientists(learn)________________alotbyanalyzingrockartfromdifferentareas.Look!Thosestudentsaretakingsamplesfromtherocks.They(study)___________________therockart.Theparkranger(give)______________________atouroftherockarttoday,butit’sbeencancelled.Astheycarvedtherock,theprehistoricartists(show)______________________anemotionsuchashappiness.canlearnwassupposedtogivemustbestudyingmighthavebeenshowingThereasonwhytheseprehistoricpeoplescreatedtherockartremainsamystery.Manyscientistsbelievetheartistsmusthavecreateditforceremonies.Othersthinktheymayhavecreateditasaformoflanguageortomarkpropertyclaims.Somepeoplehaveevenspeculatedtherockartcoulddepictvisitsfromaliensorpeoplefromouterspace,butmostscientistsdon’tthinkthisistrue.Amuchsimplerexplanationisthattherockartcould

justbetheinnocentdrawingsofancientpeoples.Whateverthereason,wemayneverknow.Artistscreatedtherockartoveralongperiodoftimeandavastgeographicarea.DegreesofCertainty:presenttenseTherockartcoulddepictvisitsfromaliens.Therockartmusttellastory.

must 95%sure

may

might 50%sureorless

couldWhichoneismorecertain?DegreesofCertainty:pasttenseTheartistsmusthavecreateditforceremonialpurposes.Othersthinktheymayhavecreateditasaformoflanguage.modal+have

+pastparticipleWhichoneismorecertain?Negative:Inbothpresentandpast,thedegreesofcertaintyformodalschange(exceptformust).Therockartcouldn’tdepictvisitsfromaliens.Therockartmaynottellastory.

couldn’t 99%sure

can’t

mustnot 95%sure

maynot 50%sure

mightnot orlessWhichoneismorecertain?PRESENTNegative:Inbothpresentandpast,thedegreesofcertaintyformodalschange(exceptformust).Theartistscouldn’thavedepictedvisitsfromaliens.Theartistsmaynothavewantedtotellastory.

couldn’thave 99%sure

can’thave

mustnothave 95%sure

maynothave 50%sure

mightnothave or