Then I'm gonna draw two lines straight down.

然后画两条垂。

And if it's bending towards this normal line...

如果它的折射光靠近这条垂。

Above what Harry assumed was the title of the story (being unable to read runes, he could not be sure) , there was a picture of what looked like a triangular eye, its pupil crossed with a vertical line.

在认为那故事的题目（他不会读古代魔文，因此他并不能确定），这一张看起来像三角形眼睛的图片，瞳孔处有一道垂。

And what the carpenter did, because he was quite a clever chap, is he went to stand on that spiral staircase and he let his plumb line down and he drew it back up.

而木匠做的， 因为他个相当聪明的，他站在那螺旋楼梯上， 放下他的铅垂， 然后又收了回来。

For example, it is known that if we draw perpendiculars to the sides of a triangle from the opposite angles, all three perpendiculars meet in a point.

例如，众所周知，如果我们从相反的角度向三角形的边绘制垂，则所有三个垂都会交于一点。

Sivert especially had a genius for knocking in nails, but Eleseus was better at handling a plumb-line.

Sivert 尤其擅长敲钉子， 但 Eleseus 更擅长处理铅垂。

Drake would have learned to feel his way along the coast with his lead line.

德雷克应该学会了用铅垂沿海岸摸索前进。