单项选择题

A．the eye's adaptation to colorB．the properties of colo……

This selection is primarily concerned with ______.

A．the eye's adaptation to color
B．the properties of colored surfaces
C．the color of colors
D．the effect of changes in color intensity

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热门试题

单项选择题During the Middle Ages, productivity of labor ______.

A．was a primary concern of society
B．was hampered by class relationships
C．began to improve over levels reached by the Greeks
D．was in a period of technical progress

单项选择题A problem that has plagued some fictional Utopias is ______.

A．creation of super-apes
B．the necessity of breeding super-humans
C．the necessity of breeding subhumans
D．the degradation of beasts