单项选择题

There is no question but that Newton was a highly competent Minister of the Mint. It was mainly through his efforts (41) the English currency was put on (42) satisfactory basis at a difficult time. (43) discovered a relationship between prices and (44) amount of money in circulation, which (45) later formalized in the so-called "quality (46) "of money: if the amount of (47) in circulation is doubled--other things (48) the same--then prices also will (49) double. This is a simple application (50) the principle that it is impossible (51) . get something for nothing, but apparently (52) took someone like Newton to discover it. There (53) an obvious comparison with Copernicus, who (54) the Polish government on currency questions (55) in doing so discovered another important (56) (usually known as Gresham’s Law): when (57) money is accepted as legal tender, (58) money will be driven out of (59) . Copernicus anticipated Gresham in the formulation (60) this law.