我被打断了，思路也断了。

I was interrupted and lost my ___train ___of ___thought.

让我们跟着作者的思路来理解这个复杂的章节。

Let's follow the author's ___train ___of ___thought through this complex chapter.

她哲学性的思考脉络让学生们难以掌握。

Her philosophical ___train ___of ___thought was difficult for the students to grasp.