In many parts of the world renewable energy is already a principal energysource.
在世界许多地方，可再生能源已经是一种主要的能源来源。
2
In a recent speech in Iowa, he dismissed wind power as an unreliable energysource.
最近在爱荷华州的一次演讲中，他将风力发电视为一种不可靠的能源。
3
All right folks, let's continue our discussion of alternative energy sources and move on to what's probably the most well-known alternative energysource—solar energy.