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.

主要角色之间的对立构成了叙事的真正主线。

The antagonism between the main characters forms the real ___thread of the narrative.

教授巧妙地将各种论点编织成一个连贯的脉络。

The professor skillfully wove the various arguments into a coherent ___thread.