参考答案:
One might ask why speculation is permitted when there is so real a danger of loss. The basic reason is that speculation can perform useful functions in the market equilibrium and encourages faster entry of more suppliers. If the price change lagged until after an actual commodity shortage had occurred, the fluctuation would probably be sharper and more sudden. Remedial supply action could not be further delayed. Similarly, if speculators foresee a surplus in some commodity, their selling of futures will help drive the price down to some extent before the surplus actually occurs. When speculators foresee a shortage and bid up the price, they are also helping to conserve the present supply. As the price goes up, less of the commodity is purchased; a rise in price encourages users to economize. Similarly, a lowering of price encourages users to buy more, thus helping to sell the surplus which is developing．