单项选择题
A．most North Americans would be unlikely to shift their diets simply in order to accommodate the exigencies of water conservation
B．the gains provided by diets with less water-intensive production would likely be less useful in areas with greater aquifer resources
C．people in Asia and certain European countries are dependent on meat-products and could not do without them
D．diets with less water-intensive production tend to be less healthy than those with more water-intense production
E．governments of certain countries would be unlikely to promote programs for diet change given their possible negative effect on those countries' economies
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（）
单项选择题 According to the passage, which of the following is true concerning optical computers（）