题目内容：
根据以下材料回答题 Readingisnottheonlywaytogainknowledgeoftheworkinthepast．Thereisanotherlargereservoir(知识库)whichmaybecalledexperience,andthecollegestudentwillfindthateverycraftsman(工匠)hassomethinghecanteachandwillgenerallyteachgladlytoanycollegestudentwhodoesnotlookdownuponthem．Butthedemonstration(示范)andreportofwhathappens,andhowithappensarecorrectevenifthereportsareincompletelyunscientificterms(术语)．Presentlythecollegestudentwilllearn,inthiscasealso,whattoacceptandwhattoreject．
Anothersourceofknowledgeisthevaststoreoftraditionalpracticeshandeddownfromfathertoson,ormothertodaughter,ofoldcountrycustoms,offolklore(风俗)．Allthisisverydiffi-cultforacollegestudenttoexamine,formuchknowledgeandpersonalexperienceisneededheretoseparategoodplantsfromwildgrass．Thecollegestudentshouldlearntorealizeandrememberhowmuchofrealvaluesciencehasfoundinthiswide,confusedwilderness．
Inthelastparagraphthephrase"thiswide,confusedwilderness"refersto__________． A．personalexperience
B．wildweedsamonggoodplants
C．theinformationfromtheparents
D．thevaststoreoftraditionalpractices
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答案解析：