单选题 My younger brother is the only one of the students who ____________ chosen to join the air force.

【正确答案】 A
【答案解析】主谓一致。我弟弟是惟一被选中参加空军的学生。A在“one of+复数名词+who／ that／which”引导的定语从句结构中，当one之前有the (only)等修饰语时，从句的谓语动词应用单数形式。