单项选择题
A．save electricity by converting unused sunlight into power through the use of photocells
B．waste less electricity by insulating and reducing resistance in the conduits of the power grid
C．increase electrical efficiency by requiring consumers to use appliances that rely on less electricity
D．create a more reliable power grid by supplying electricity from a wider range of power plants
E．reduce the electricity necessary to powering a city by encouraging denser population growth
单项选择题 According to the passage, the main disadvantage with reconfiguring diet to lessen water usage is（）
单项选择题 The passage suggests that the author would most probably agree with which of the following assessments of optical computing in its present form（）
单项选择题 It can be inferred from the passage that the author would be more optimistic about optical computing if which of the following were true（）