The manager was worried about the press conference his assistant in his place but luckily

网友回答

A. gave
B. gives
(答案→)C. was giving
D. had given
解析：考查时态：从题意“经理很担心助手正在代他参加的新闻发布会，但幸运的是，一切进展顺利，可知，give这一动作和was worried about同时存在，还有everything was going on，说明是过去正在进行，根据题意可知应用过去进行时。选C。