Level 2: Defining for each wave a specific change initiative.
层次2：确定每个波动的具体变化开端。
2
Sensors detect when dust concentrations reach a critical level and then an electric charge energises the material sending a dust-repelling wave across its surface.
当传感器发现粉尘浓度达到了临界水平，就有一定的电荷促使该材料发出除尘波越过其表面。
3
At our current level of technology, no conceivable mix of solar, wind, or wave can meet even half the demand for energy.