浙江省金丽衢十二校高三第一次联考
阅读下面短文，根据所给情节进行续写，使之构成一个完整的故事。
Rebeccastretchedhertiredback.“That’sthelastseedling(种树苗)，Pa.Haveweplantedenough?”
Pawalkedtotheendoftherowofcottonwoodseedlings.“No,”hesaid.“Wehavetoplanttreesallthewaytothatrockoverthere.We’llneedabouttwentymoreseedlings.”
“I’llgettheseedlings.”offeredRebecca.Shelongedtocoolherfeetintheshallowriverrunningthroughthecottonfield.
“You’dbetterletmego,MissPetticoats,”teasedhertwinbrother,William.“Therearedangersalloverthisprairie(牧场/草原）
“Youmaybothgo,”saidPa.“Buthurryback.I’dliketofinishbeforesundown.”
Theywentacrosstheshallowrivertoasandbarwheresmallcottonwoodseedlingsgrew.
Gently,theypulledtheseedlingsfromthesand.
“There!That’stwenty,withafewtospare.”saidRebecca.
“OK，”saidWilliam.Heledthewaytotheriverbank,thenstopped.“Look!There’sthedugout(防空壕）welivedinwhenwemovedherelastyear.”Hepointedtoaholeinthegrassyriverbank.
“Comeon,let’sgoinside.”
“No，”Rebeccasaid,“Paiswaiting.Besides,it’shardtellingwhat’sinthere.”
“Thenyoustartback.”saidWilliam,handingtheseedlingstoRebecca.I’llcatchup.”Herantothedugoutandsteppedinside.
Rebeccatiedtheseedlingsintoherlongapron(围裙）andbegantowalk.Suddenlyshefrozeinhertracks.
Ahugeprairierattlesnake(响尾蛇）movedalongtheriverbank.
Itstoppedrightinfrontofthedugoutandlaystill,coileduponthewarmsunnybank.
“William!”Rebeccashouted.“Don’t