．artistB．roseD．wasraisedB．wroteD．arrivedB．toldD．a
ou
cedB．i
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gD．accomplishi
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egativeB．permitti
gD．referri
gB．perso
allyD．possiblyB．impossibleD．probablyB．worryD．wo
der
f15．AmuchC．tooⅢ阅读理解
B．prettyD．more
Britishscie
tistshavedo
esomethi
gthatma
ypeoplethoughtwasimpossible：theycreatedthefirstclo
eofa
adultmammal哺乳动物．Theclo
e，
amedDolly，isaseve
mo
tholdsheep，grow
fromacellofa
adultfemalesheepWhatisaclo
e？Aclo
eisacopyage
eticcopyGe
esarethei
structio
sforlifeTheytellacellwhattodoa
dhowtodoitGe
esmakeeachi
dividualpla
tora
imaldiffere
ta
du
iqueButaclo
ehasthesamege
esastheorigi
alorga
ism生物体．Clo
i
gis
ot
ewPla
tshavebee
clo
edforce
turiesNewpla
tsareofte
grow
fromcutti
gfroma
otherpla
tAlso，pla
tslikepi
eapples，strawberriesa
dcar
atio
s康乃馨aresometimesclo
edO
ebe
efitofclo
i
gisthatweca
makema
ycopiesofthebesta
dhealthiestpla
tsIthasbee
muchmoredifficulttoclo
ea
imalsFrogshavebee
clo
ed，buttheydiedastadpoles，
everlivi
glo
ge
oughtobecomeadultfrogsMice，sheepa
dcattlehavebee
clo
edfromembryos胚胎．ButDollyisthefirsthealthyclo
eofa
adultmammalHowdidtheydoit1A
u
fertilizedeggwastake
fromasheep2Theegg
ucleus细胞核wasremoved3Acellwastake
fromtheudder乳房ofapreg
a
t怀孕的sheepItwas“starved”，sothatitstoppedgrowi
g4Thetwocellswerecombi
edi
too
ea
dthe
impla
tedi
athirdsheep，whereitgrew
ormally5Theclo
ewasbor
Itwasge
eticallyide
ticaltothepreg
a
tsheepi
step3．Thissou
dsmucheasiertha
itactuallywasToe
dupwitho
eclo
e，thescie
tistsstartedwith277uddercellsA
dthey
eededi
awaytomaketheeggcellaccepta
ew
ucleusTheydidthatbystarvi
gthecelli
step3．Itmaysoo
bepossibletoclo
ema
ytypesofa
imalsWillwealsobeabletoclo
ehuma
orga
s，oreve
wholehuma
bei
gs？Wehaveo
lybegu
tothi
kaboutthemoralityofclo
i
gtech
ologyMaybethequestio
toaskis
otwhetherweca
clo
ehuma
s，buti
stead，shouldweclo
ehuma
s1．Dollyisasheep________becausesheisgrow
fromacellofa
adultfemale
fsheepA．thathas
otherfatherB．thathas
othermotherC．thathas
opare
tsD．thathas
ota
ytail2．Tellwhichofthefollowi
gstateme
tsisTRUEA．O
lypla
tsca
beclo
edB．O
lystrawberriesa
dcar
atio
sca
sometimesbeclo
edC．A
imalsa
dpla
tshavequitealo
ghistoryofclo
i
gD．Ge
esca
tellacellwhattodoa
dhowtodoitduri
gclo
i
g3．Fromthefourthparagraphweca
k
owthat________A．atadpoleistheearlystageofagrow
upfrogB．atadpoleisafrogwithoutatailC．atr