Intheoriginaltest，alltheanimalsinatestgrouparegivenasubstance_______halfofthemdie
A、unlessB
本題考查詞義辨析。 until：直到。符合句意，表示 given a substance 持續(xù)到 half of them die 。
Whathehaddoneis_______
TheAdventuresofTomSawyerand,especially,itssequence()provedthemselvestobethemilestoneintheAmericanliterature.
AftertheAmericanCivilWar,theliteraryinterestintheso-called“reality”oflifestartedanewperiodintheAmericanliterarywritingsknowantheAgeof().
TheeffectofDarwinistideaof“survivalofthefittest”wasshatteringin()’sfictionalworldofjungle,where“killortobekilled”wasthelaw.
In1950,oneoftheleadingAmericanwriters()wasawardedtheNobelPrizefortheanti-racistIntruderintheDust.
