Then,seventy-million years ago, the Earth's surface, or crust,pushed upward.

VOA: special.2010.01.04

There are - that's one class of proteins on the surface I'm sorry.

对不起,这是细胞膜蛋白的一个种类

耶鲁公开课 - 生物医学工程探索课程节选

The U2 was brought down by an S-2 surface to air missile.

VOA: standard.2010.05.07