【题目】A study shows the students who are engaged in after-school activities are happier than _________who are not.
A. onesB. those
C. theseD. them
在线课程【答案】B
【解析】
考查代词。句意：一项研究表明，参加课外活动的学生比不参加课外活动的学生更开心。空格处代词与the students是对应关系，可以用the ones或者those替代。“them”指代的是前边提到的复数名词，不能与the students形成对应关系。“these”一般不用定语从句修饰。故选B。