今天的句子：
Today’s minimum energy performance standards for an air conditioner are about 40% of the best technology available, Mr. Campbell says. If that requirement changed upward, it could save consumers tremendous amounts of money on their utility bills, and also take pressure off electrical grids, which, in recent years, have crashed because of spikes in demand during heat waves. And if manufacturers were required to make more of the higher-efficiency units, their costs would eventually fall as well.
思考题：
It can be inferred from the text that__.
A. high-efficiency technologies have not been invented yet
B. the current electricity price in U.S. stay on a low level
C. electrical grids are in good shape despite heat waves
D. making higher-efficiency units incur higher cost now
句子解析：
第一句：
Today’s minimum energy performance standards （主语） for an air conditioner are about 40% of the best technology available, Mr. Campbell says.
参考译文：坎贝尔先生说，现下空调的最低能源性能的标准约为已有最佳技术的40%。
第二句：
If that requirement changed upward, it could save consumers tremendous amounts of money on their utility bills, and also take pressure off electrical grids, which, in recent years, have crashed because of spikes in demand during heat waves.
参考译文：如果将标准向上调，可为消费者节省大笔水电费，并减轻电网压力，近年来，由于热浪时期需求激增，电网曾经崩溃。
第三句：
And if manufacturers were required to make more of the higher-efficiency units, their costs would eventually fall as well.
参考译文：如果制造商必须生产更多的高效率设备，那么它们的成本最终也会下降。
思考题解析：
A. high-efficiency technologies have not been invented yet
（高能效技术还没有发明出来）
A选项错误。
B. the current electricity price in U.S. stay on a low level
（美国目前的电价处于较低水平）
B选项错误。
C. electrical grids are in good shape despite heat waves
（尽管有热浪，电网仍状态良好）
C选项错误。
D. making higher-efficiency units will incur lower cost
（现在生产更高能率的空调将带来更低的成本）
对应最后一句！
D选项正确。
文章来源背景和来源：
Can people stay cool without warming the planet?
人们能保持凉爽又不让地球变暖吗？
Source: https://www.csmonitor.com/Environment/2022/0817/Air-conditioning-Can-people-stay-cool-without-warming-the-planet
背景：随着热浪席卷北半球，人们越来越注意到一个现象，即越来越多的人需要空调且需求的时间也愈加久，另外经济的发展也让更多人能负担起空调使用的费用。但空调和电扇的耗电量已经占全球室内用电的五分之一，而空调造成的温室气体排放已占全球的4%。越热越需要空调，越用空调越多温室气体排放，这个恶性循环已引起了政策制定者、工程师、学术界及企业家的关注。目前最先进的制冷技术已经可以实现相当高的能源效率，但市面上的空调普遍只能达到理想效率的40%，因为大部分生产商的重点并不在环保和节能，而是怎么降低成本，通过低价占领更大的市场。专家们认为，应用高能效技术是解决问题的方法之一。
