SinceJanuary2013manycitiesinChinahaveseenalotoffoggydays.InBeijingonlyfivedaysinJanuarywerefreeofsmog(雾霾).What’sthedifferencebetweenfogandsmog?Accordingtoscientistsfogismadeupoftiny(

SinceJanuary2013manycitiesinChinahaveseenalotoffoggydays.InBeijingonlyfivedaysinJanuarywerefreeofsmog(雾霾).What’sthedifferencebetweenfogandsmog?

Accordingtoscientistsfogismadeupoftiny(微小的)dropsofwaterandalsoiceparticles(颗粒)duringverycoldconditions.Smogisdirtyairthatlookslikeamixtureofsmokeandfogcausedmainlybysmokefromcarsandfactoriesincities.

AnofficialfortheMinistryofEnvironmentalProtectiontoldBeijingNewsthatPM2.5pollutionisthemainproblemwithairpollution.PM2.5referstopollutionwithsmallparticles2.5micrometersorlessindiameter(直径).

AccordingtotheChineseAcademyofSciencestwomainfactorsthatcausePM2.5aremotorvehiclesandtheburningofcoal.

Poorairhasdoneharmtopeople’shealth.Childrenandtheelderlyaremoreatrisk.AreportfromBeijingChildren’sHospitalshowsthatfromJanuary5toJanuary112013halfofthepatientsinthehospitalcameforrespiratory(呼吸道的)problems.

TorespondtotheairproblemtheChinesegovernmentandmanyChinesepeoplehavestartedtotakeaction.

Beijingannouncedaplantousecleanfuelingovernmentvehiclesandplanttrees.ItaskedcitizenstosetofffewerfireworksfortheSpringFestivalcelebration.Theysuggestedthatcarswithlargeemissions(排放)shouldbebannedandfactoriesshouldbecloselywatched.

ThreestudentsfromNo.4HighSchoolinBeijingwroteareporttoadvisetofighttheairpollution.“Wehopemorepeoplewilljoinustoprotectourenvironment.Withalloureffortstheblueskieswillcertainlyreturnsoon”saidShiYucong15oneofthethreestudents.

1.Theunderlinedphrase“werefreeof”means____________.

A.hadsome B.hadmany C.hadno D.hadmoreandmore

2.Accordingtothesecondparagraphwecanknow____________.

A.smogisamixtureoffogandsmoke B.smogisformed(形成)duringcoldhours

C.fogismadeupofdropsofwaterwithsmoke D.smokefromcarsandfactoriescausefog

3.Paragraphs3and4aremainlyabout____________.

A.whatPM2.5isandwhatcausesPM2.5

B.howtopreventPM2.5pollutionandhowPM2.5looks