thread

我阅读了关于年长母亲的讨论串。

I read the ___thread about older mothers.

到那时我已经跟不上对话的脉络了。

By that point I'd lost the ___thread of the conversation.

她发起了一个新讨论串来讨论最新电影的上映。

She started a new ___thread to discuss the latest movie release.