Their waste then acts as a cover.

VOA: special.2010.07.13

We have a weight on the piston, and that weight is chosen so that p2 it acts as though p external is equal to p2.

让活塞上放一重物，让它的效果刚好,等同于外压强。

麻省理工公开课 - 热力学与动力学课程节选

The drug acts as a blood thinner.

VOA: special.2009.09.01

And Turkey acts as a buffer on Iran's border from the encroachment of Western NATO powers and to some extent Israel.

VOA: standard.2010.07.26

Bretton Woods Project, an NGO that acts as a watchdog to scrutinize "The problem is which countries will be able to access this credit line.

VOA: standard.2009.04.20

They believed that signs of crime, such as broken windows in a building, led to other acts of crime.

VOA: special.2009.03.03

But a majority don't think it is going to work in terms of being able to stop terrorists there from using Afghanistan as a terrorist base to do terrorists acts against the United States."

VOA: standard.2009.10.09