<长篇阅读二 能源变更的困难性>

　　The impossibility of rapid energy transitions

　　本篇文章出自《世界观察》(World Watch)，主要解释了能源不可能快速变更的原因。文章首先介绍了能源以能量体系的形式存在，对大体概念进行介绍。接下来文章分别介绍了technological momentum(D段至H段)。Labor-pool momentum(I段)和economic momentum(J段)。最后两段作为总结，重申不能快速改变的原因和我们对这个话题应持有的态度。

　　46. Not only moving objects and people but all systems have momentum.

　　答案【C】

　　47. Changing the current energy system requires the systematic training of professionals and skilled labor.

　　答案【I】

　　48. Changing a light bulb is easier than changing the fixture housing it.

　　答案【E】

　　49. Efforts to accelerate the current energy transitions didn’t succeed as expected.

　　答案【K】

　　50. To change the light source is costly because  you have to change the whole fixture.

　　答案【G】

　　51. Energy systems, like an aircraft carrier set in motion, have huge momentum.

　　答案【A】

　　52. The problem with lighting, if it arises, often doesn’t lie in light sources but in their applications. 答案【G】

　　53. The biggest obstacle to energy transition is that the present energy system is too expensive to replace.

　　答案【J】

　　54. The application of a technology can impact areas beyond itself.

　　答案【D】

　　55. Physical characteristics of moving objects help explain the dynamics of energy systems.

　　答案【B】