问题
选择题
On Saturdays, students are very proud to be on the street to guide passers-by to obey traffic rules.
A．characters
B．volunteers
C．operators
D．graduates
答案
B
题目分析：A. characters人物，性格，B. volunteers 志愿者，C. operators接线员，操作员，D. graduates毕业生，句意：在星期六，学生很自豪能做街上的自愿者指导行人遵守交通规则。根据句意选B.