Wuhan，thecapitalcityofHubeiprovince，hasissuedsmogwarningsforthreedayssinceMondaybecauseofseriousairpollution．

Thelingeringsmogforcedconstructionsitestostopworkandprimaryandmiddleschoolstosuspendoutdooractivities．FromMondaythroughWednesday，thecity'sairqualityindexreadingremainedhigh，withthehighestreadingat323，withPM2.5，orparticulatemattersmallerthan2.5microns，asthemainpollutant，accordingtothecity'smeteorologicalbureau．Anyreadingover300isconsidered"seriouslypolluted"．

ThecityexperiencedatleasteightheavilypolluteddaysinthefirsttwoweeksofDecember，withtheairqualityindexreadingreachingahighof440，ChinaNewsServicereported．

AmongthoseaffectedwasasquaredancingteaminJiang'andistrict，whichhadtostopdailypracticesafterseveralmembersfellill．Squaredancingisacommonopen-airfitnesspracticeacrossChina，withmostoftheparticipantsmiddle-agedorelderlywomen．

MediareportedtheleaderofonedancingteamhadtogotoahospitalaftershehadanasthmaattackonDec11．

IdentifiedonlyasFang，65，thedanceteamleadersaidshedecidedtosuspendthepracticesaftershelearnedherillnesswascausedbysmog，andafterseveralothermembersalsofellill，thereportsaid．

Thecityplanstoinvest28billionyuan（$4.61billion）inairpollutioncontrolby2017．Theplansaysthecitywillboostthedevelopmentofcleanenergyvehiclesforpublictransportationandremoveallofthecurrent140，000heavy-pollutingvehiclesfromWuhan'sroadsbytheendof2016．

67．What'sthemainideaofthepassage？___

A．Wuhandecidedtoremovemostconstructionsites．

B．Wuhanissuedsmogwarningsforthreedaysbecauseofsmog．

C．Thecityisreportedlyunfitforphysicaltraining．

D．Outdoorexercisecandecreasetheinfluenceofsmog．

68．Theairqualityindexreadingofthecityoncereachedtoanextremeof___．

A.300 B.323 C.440 D.140，000

69．Thecityauthoritieswillfirstlydevelop___inthefuture．

A．greentransportation

B．environmentallyfriendlyenergy

C．heavyvehicles

D．trans