请问是under discussion or in discussion?

帮俺做道题His ideas___the topic under discussion in the meeting. from what has been under discussion join in the discussion 还是join the discussion ____ we will do next is still under discussion.这里是主语从句吗?怎么分析 英语"discussion 英语翻译everyone in the discussion对吗 in the light of the discussion ______work is very important in a discussion. When I went in ,they were_ in a heated discussion. 请问国外Discussion Paper类型的文章水平如何? This was the furthest point they reached in their discussion Would you like to ______us in our discussion. A