A. necessary B. indispensable C. dispensable

单项选择题

Income vs. Leisure
Because both leisure and income are (21) ,we confront a tradeoff when deciding whether to go to work. Going to work implies more income but less leisure. Staying home has the opposite consequences.
The (22) tradeoff between labor and leisure explains the shape of individual labor-sup ply (23) As we work more hours, our leisure time becomes scarcer—and thus more valuable. We become increasingly (24) to give up any remaining leisure time as it gets ever scarcer. People who work all week long are reluctant to go to work on Saturday. It’s not that they are physically exhausted. It’s just that they want some time to enjoy the (25) of their la bor. In other words, as the opportunity cost of job time increases, we require (26) higher rates of pay. We will supply additional labor—work more hours—only if higher wage rates are offered: this is the message conveyed by the upward-sloping labor-supply curve.
The upward slope of the labor-supply curve is (27) with the changing value of income. Our (28) motive for working is the income a job provides. Those first few dollars are really precious, especially if you have bills to pay and no other source of support. As you work and earn more, however, you discover that your most (29) needs have been satisfied. You may still want more things, but your consumption desires aren’t so urgent. In other words, the margin al (30) of income declines as you earn more. You may not be willing to work more hours unless offered a higher wage rate.

A. necessary
B. indispensable
C. dispensable
D. valued