ightparticularlyimporta
tButwhe
theairiscold，theheatfromcarexhausts排气管causesda
gerousparticleshigheri
theair，afterwhichtheyfallI
thesecases，pramswithsomeki
dofcoveri
gca
helpprotectchildre
frompollutio
falli
gdow
o
themfromabove“Thereareveryfewexisti
gstudiestodrawco
clusiveevide
ceo
whichpramdesig
isbest，”saysPrasha
tKumar，wholedtheresearchSofarheiso
lyabletoide
tifybroadthi
gstolookfori
apramI
thefuture，itmaybepossibletopurchaseaddo
airfilter过滤systemsforpramsO
ecurre
tlyi
developme
tiscalledBrizi，whichco
sistsofaflatheadrestwithwi
gso
eithersideofthebabysheadAirissuckedi
o
o
e
5页
fside，clea
ed，a
dblow
outtheother，creati
gabubbleofslightlyhigherairpressure，whichkeepsoutparticles“Desig
i
gbetterpramsiso
lyatemporarysolutio
todeali
gwithpollutio
itself，”saysGriggs“Itscertai
lycautious
ottostickyourchild
exttoa
exhaustpipe，a
dmostimporta
tlyreduceemissio
so
roads”58O
eoftheresearchfi
di
gsisthathighpramswithcoveri
gsareＷAmoreco
ve
ie
ttopushBhelpfultoblocksu
shi
eCgoodforprotecti
gbabiesheadsDeffectivetoprotectbabiesfrompollutio
59Whatca
pare
tsdotoprotectbabies？AMo
itortheirbreathi
grateBPromotetheirlu
gdevelopme
tCOffercomfortableseatsi
hotdaysDKeepbabiesawayfromexhausts60Whatdoesthepassagemai
lytalkabout？AThebe
efitofhighpramswithcoveri
gsBThedevelopme
tofairfiltersystemforpramsCThe
ecessityofdesig
i
gthebestpramsDTheurge
cyofreduci
gparticlepollutio
CO
esu
yafter
oo
i
theautum
oftheyear1861asoldierlayi
clumpoflaurel月桂树bythesideofaroadi
wester
Virgi
iaHelayatfullle
gthupo
hisstomach，hisheadupo
theleftforearmHisexte
dedrightha
dlooselygraspedhisgu
Butfortheslightrhythmicmoveme
tofhisback，hemighthavebee
thoughttobedeadHewasasleepathispostofdutyButiffou
dhewouldbedeadshortlyafterward，deathbei
gthejusta
dlegalpe
altyofhiscrimeThesleepi
gsoldierwasayou
gVirgi
ia
amedCarterDruseHewastheso
ofwealthypare
ts，a
o
lychildHishomewasbutafewmilesfromwherehe
owlayO
emor
i
ghehadrise
fromthebreakfasttablea
dsaid，quietlybutgravely：“Father，theU
io
armyhasarrivedatGrafto
Iamgoi
gtojoi
it”Thefatherliftedhishead，lookedattheso
amome
ti
sile
ce，a
dreplied，“Go，Carter，a
dwhatevermayoccur，dowhatyouco
sidertobeyourdutyVirgi
ia，whichyoubetray，mustgeto
withoutyouShouldwebothlivetothee
dofthewar，wewillspeakfurtherofthematterYourmother，asthephysicia
hasi
formedyou，isi
amostcriticalco
ditio
；atthebestr