ˈcall on/upon sb(formal)1to formally invite or ask sb to speak, etc.邀请，要求（某人讲话等）；恭请I now call upon the chairman to address the meeting.现在请主席向大会致辞。2to ask or demand that sb do sth请求，要求，要（某人做某事）I feel called upon(= feel that I ought)to warn you that…我觉得我应该警告你… |