单项选择题

Sociologists use "power" to refer to the capacity of people to control or influence the actions of others. Sociologists study power to (31) not only who exercise it, but also why it’s exercised and who benefits from its use.
Of wealth, power and prestige, power is the hardest to measure. Most studies are nothing more than an average of (32) about where power is found. Many forms of power are so (33) hidden that only its holders know the source. Because it’s so hard to (34) , and tied to ideology, the subject of power is a source of much (35) in sociology. Some maintain that power in America is concentrated in the (36) of a few people who have a common (37) and who tend to act together. Wright Mills (38) that America is (39) by a "power elite". Others believe that power in America is (40) among many groups and people.
Sociologists do agree that real power may not always lie (41) we think it does. Mayors of some cities, (42) , are sometimes mere figureheads looking impressive. The actual decisions are made by a handful of business leaders staying behind the (43) . Some are made at the lowest level, where the work is really (44) Such is the (45) with the police officers or teachers.
Power may exist (46) wealth: not all the rich are powerful, and vice versa. But the two (47) are closely related. In national politics, (48) for office are often wealthy. The Kennedy’ brothers, the Roosevelts, and Reagan are only a few men of wealth powerful in politics. Moreover, power is often used to (49) wealth. How many lawmakers, generals, or labor union heads retire (50) poverty