However, though the power of the gasoline-burning motorcar may be high, it is very inefficient. On average only about 10 % or so of the energy is converted into power for driving the shaft, while the remaining 90 % becomes waste air or waste heat. This means it is not only a profligate user of energy, it is a killer through pollution of the environment.
然而燃燒汽油為動力的引擎，其功率雖高，但是效率極低（能源在中途會消耗），平均只有百分之十左右轉化成動力，其他百分之九十則轉成廢氣、廢熱等，不只是能源的浪費，也是汙染環境的大兇手。