Many countries have put proposals to reduce emissions on the table, including the United States, China and South Africa.

VOA: standard.2009.12.08

We'll then take a turn to talking about the periodic table, we'll look at a bunch of periodic trends, including ionization energy, electron affinity, electronegativity and atomic radius.

然后我们再开始讲元素周期表，我们会看到很多周期性规律，比如电离能，电子亲和能，电负性以及原子半径。

麻省理工公开课 - 化学原理课程节选