问题
选择题
Research shows that teenagers ________ talk about their day with family members at the dinner table are less likely to engage in high-risk behavior.
A．what
B．who
C．whom
D．\
答案
答案：B
题目分析：考查定语从句：句意：研究表明在餐桌旁和家人谈论一天发生的事情的年轻人不太可能参加一些高危的活动。先行词是the teenagers，定语从句中缺少主语，用who引导定语从句，who不能省略，选B。
牙根折断，经手术拔除