新概念英语第二册第一课中过去进行时问题？

因为这是“我”回忆的,有具体时刻,是“我”当时所见所闻.

表示原来正在做某事用一般过去进行时 一般此类句子会有过去的某个时间点 比如：She was doing her work at 8:00 last night.

表示原来做过某事 不强调具体时间点正在做的 用一般过去时,1,因为这是一种状态，表示的是他们坐在后面的一种状态。,1,(1)表示原来正在做某事用一般过去进行时 一般此类句子会有过去的某个时间点 比如：She was doing her work at 8:00 last night.

(2)表示原来做过某事 不强调具体时间点正在做的 用一般过去时,0,新概念英语第二册第一课中过去进行时问题

Last week I went to the theatre.I had a very good seat.The play was very interesting.I did not enjoy it.A young man and a young woman were sitting behind me.They were talking loudly.I got very angry.I could not hear the actors.I turned round.I looked at the man and the woman angrily.They did not pay any attention.In the end ,I could not bear it.I turned round again.’I can't hear a word!' I said angrily.

’It's none of your business,' the young man said rudely.This is a private conversation!”

A young man and a young woman were sitting behind me.为什么用过去进行时,而不是一般过去时?

一般在什么情况下用过去进行时?