The Environmental Protection Agency, is keeping a close watch on threats to the delicate eco-system along the coastline.

VOA: standard.2010.05.18

Now they get close enough together that they start to sense that they are becoming part of one system.

现在他们足够接近了,它们开始作用了,他们开始成为体系的一部分。

麻省理工公开课 - 固态化学导论课程节选

Now, what if they get close enough together to start forming one system.

现在组成为一个整体,会发生什么。

麻省理工公开课 - 固态化学导论课程节选