题目内容：
根据以下材料，回答题 Inhisyouth,KnuteAxelbrodwantedtolearnmanylanguagestoknoweverythingabouthumanhistory,to41wisebyreadinggreatbooks．WhenhefirstcamefromEurope
42thestateofNorthDakotA．heworkedinamillallday43studiedallevening.
ThenhemetLenaWesseliusand44herattheageofeighteen．Afterthattherewasafarmtopayfor,andtherewerechildrento45．FormanyyearsAxelbrodhadnotimetostudy．Finallyhehadafarm46wasfreefromdebt,withgoodsoilandplentyofanimals．But47thenhewassixty-threeyearsoldandready(itseemed)todie．Hiswifewas48．Hissonshadgrown49andgoneaway．Hisworkwasdone．Hewas50.
andalone．Axelbrod'sdaughterand51beggedhimtolivewiththem,buthe52"No,"hesaid,"Youmustlearntobe53．Youwillcomeandlivehere54myfarm,and55willpaymefourhundreddollarsayear56theuseofit,57Iwillnotliveherewithyou．Iwillwatchyoufrommyhill."Hebuilthimselfasmallhouseonthehill,58hecookedhis59,madehisbed,andreadmanybooksfromthepubliclibrary.
Hebegantofeelthathewas60freethaneverbeforeinhislife.
第41题答案是________ A．be
B．grow
C．become
D．turn
参考答案：
答案解析：