本章分析了在消费者可以按利率，_储蓄或借贷的情况下的费雪模型，以及消费者可以按这种利率储蓄但完全不能借

贷情况下的费雪模型。现在考虑消费者可以按利率r_s储蓄，并按利率r_b借贷，且r_s＜r_b的中间情况。

a．在消费者第一期消费小于第一期收入的情况下，消费者的预算制约是什么？

b．在消费者第一期消费大于第一期收入的情况下，消费者的预算制约是什么？

c．画出两条预算制约线以及代表消费者可以选择的第一期与第二期消费组合的阴影面积。

d．现在加上你画的消费者无差异曲线。说明三种可能的结果：一种是消费者有储蓄，另一种是消费者有借贷，而第三种是消费者既无储蓄又无借贷。

e．什么决定了这三种情况中每一种情况下的第一期消费。

The chapter analyzes Fisher's model for the case in which the consumer can save or borrow at an interest rate of r and for the case in which the consumer can save at this rate but cannot borrow at all. Consider now the intermediate case in which the consumer can save at rate r_sand borrow at rate r_b, where r_s＜r_b.

a．What is the consumer's budget constraint in the case in which he consumes less than his income in period 0ne？

b．What is the consumer's budget constraint in the case in which he consumes more than his income in period one？

c．Graph the two budget constraints and shade the area that represents the combination of first-period and second-period consumption the consumer can choose.

d．Now add to your graph the consumer's indifference curves. Show three possible outcomes: one in which the consumer saves, one in which he borrows, and one in which he neither saves nor borrows.

e．What determines first-period consumption in each of the three cases？