Swithin, in the room overhead, had suspended his calculations, for the duologue interested him.

在头顶房间里，斯维辛暂停了他计算，因为二重奏引起了他。

The hollow spiral, as he knew from old experience, would bring down to his ears the slightest sound from above; and it now revealed to him the words of a duologue in progress at the summit of the tower.

他从过去经验知道，空心螺旋线会把上面最轻微声音传到他耳朵里；现在，它向他揭示了顶正在进行对白话。