问题:
[不定项选择题]
Traffic in Our CitiesThe volume of traffic in many cities in the world today continues to expand.This causes many problems,including serious air pollution,lengthy delays,and the greater risk______(1)a
A、thought
B、case
C、event
D、thing
试题来源参考:河南成人高考题库,青书学堂学习平台,专升本层次,医学检验技术专业,第1学期,大学英语1题库,函授题库