八上阅20Haveyoueverseenahorsewithtoes(脚趾)
Millionsofyearsago,horseshadmanytoes
Theyhadfourtoesoneachfrontfoot
Theyhadthreetoesoneachbackfoot
Thesesmallhorseslivedintheforests
Buttoeshelpedthemrunoverthesoft,wetground
Itwasonceveryhotintheforests
Buttheweatherchangedlater
Itbecamecold
Manytreescouldnotliveinsuchweather,sotheydiedandfelldown
Openfieldstooktheplaceofforests
Thesunmadethegrounddryandhard
Horsesbegantogetbiggerwithclimate(气候)changing
Onthedry,hardland,horsesneededonlytheirmiddletoesforrunning
Theirmiddletoesbecamehard
Afteralongtime,horseshadonlyonehardtoeoneachfoot
Wecallit“hoof”
Longago,thehorsehadfourtoesoneach
frontfootB
backfootC
leftfootD
rightfoot2
Whatdidthehorseneedonthedry,hardland
OnlytheirmiddletoeforrunningB
AlotofroomforrunningC
StronglegsD
Harderfeet3
Themain