1.【2018·北京】5. She and her family bicycle to work, _________ helps them keep fit.
A. which B. who C. as D. that
【答案】A
【解析】考查非限制性定语从句。句意:她和家人骑自行车去上班,这有助于她们保持健康。“____ helps them keep fit”是非限制性定语从句,该从句修饰整个主句,引导词在从句中做主语,故该从句应用关系代词which引导。A选项正确。
点睛:非限制性定语从句即可修饰主句的一部分,也可以修饰整个主句。其引导词的选择和限制性定语从句的判断规则一致,即:第一、找准先行词;第二、看先行词在定语从句中所作的成分。需要注意的是,that不能引导非限制性定语从句。