问题 更新时间2023/4/3 12:59:00 Working hours in the United States ____ over the past 20 years. ( )(本题2.5分) A、 were increasing B、 have been increased C、 have increased D、 increased 答案 登录 注册 标准答案:C 出自:青书学堂 >> 西安石油大学-石油工程技术-大学英语I(上)