Researchshowsthatthoughstudentsbenefitfromhavingparentsinvolvedatschool,

Research shows that though students benefit from having parents involved at school, _____ happens at home matters much more.A.whichB.whatC.thatD.whether

B解析试题分析：考查主语从句。本题的what引导起主语从句what happens at home，并在句中作主语。CD两项不能在句中做主语，which是指特定范围之内的某一个。故B正确。考点：考查主语从句的连接词点评：名词性从句的考查集中在引导词的选择上，连接词that, whether, if在句中不充当任何成分，只起连接作用；连接代词who(ever), which(ever), whom(ever),whose(ever),what(ever)在句中做主语，宾语，表语和定语；连接副词when, why, where, how，在句中做状语。应从上下句的句法关系着手分析，切不可‘望句形生

这个解释是对的