Okay. Now the strings.Turn it up just a little bit.

好,现在是弦乐器,音量开大点

耶鲁公开课 - 聆听音乐课程节选

So we know that it'll go up for one second then it will turn around and come back.

我们知道了,物体在上升一秒后开始下降

耶鲁公开课 - 基础物理课程节选

The nucleotide has a directionality, there's an up and a down to it and it's going to turn out the chain that's formed by polymerizing these has a directionality as well and that's important in defining the structure.

核苷酸有方向性,有上端和下端,核苷酸长链,是由核苷酸沿一个特定方向聚合而成的,这在定义结构时很重要

耶鲁公开课 - 生物医学工程探索课程节选

So, we know it's going to go up and turn around and come down.

我们知道物体会先上升然后调转方向下落

耶鲁公开课 - 基础物理课程节选