—How many times have you been to the Site of Zunyi Meeting?

—In fact, it is the first time I ________here.

A．was

B．am

C．had been

D．have been

某施工现场三位工人发现安全隐患，则以下属于这三位工人的义务的是（）

A.迅速记录事故发生经过

B.立即停止作业

C.迅速通知所有在场人员撤离

D.迅速向该单位负责人报告