But the threat of terrorism, according to former Yemeni prime minister Abdul Karim al-Iryani, is equally part of the downward economic spiral causing anger on the streets of Sana'a.

VOA: standard.2010.04.20

Everything is interconnected on the higher level on a spiral-- in other words will lead to deep understanding and hopefully assimilation of the material.

所有内容在一个更高的水平上呈螺旋状互相联系-,换言之，会带来深刻的理解和我所希望的对材料的吸收。

哈佛公开课 - 幸福课课程节选

It goes out to the outside world, interacts,gets its hand and mind dirty, does work outside and then applies its work and learns from "the dirty experiences" and brings it back to the lab and so on and so on in an upward spiral.

而是走到外面的世界，与外界互动，接触那些“肮脏“事物，在外面工作，并吸取经验,从“肮脏经验“中学习“,将得到的经验带回实验室,诸如此类，就像一个上升的螺旋。

哈佛公开课 - 幸福课课程节选