问题 更新时间2023/4/3 12:59:00 10. Building that railway was very difficult and involved _____ ten tunnels.A. dig B. throwing C. to have thrown D. having thrown 答案 登录 注册 B 出自:青书学堂 >> 河北建筑工程学院-建筑工程技术(专科)-大学英语1