问题补充:
--- Did you notice him come into the hall?
--- Sorry, sir. I with my friends online.
A. was chatting
B. chatted
C. would chat
D. am chatting
答案:
(答案→)A. was chatting
B. chatted
C. would chat
D. am chatting
解析:句意:你注意到他进入大厅了吗?——抱歉,先生。我(当时)正在和我的朋友在线聊天。结合语境可知下文描述的是过去某时正在进行的动作,故用过去进行时态。选A。