在Book 5的55页提到了Real Option, 这个到底是什么样的option啊，看不太懂。。。。。求高手解释！

Real options under uncertainty.

producers are holding valuable real options— options to produce or not to produce—and will not exercise them unless the spot prices start to climb up. Production occurs only if discounted futures prices are below spot prices, and backwardation results if the risk of future prices is sufficiently high. A major consequence of a downward- sloping term structure of futures prices is the opportunity to capture a positive roll return as investment in expiring contracts is moved to cheaper new outstanding contracts.

原来这里的producer是利用原油生产其他产品的啊，还一直以为是生产原油的。

可是为什么要当它的期货价格低于现价，才会开始实施这个option呢？

市场显示原材料价格下跌，你是多进货还是少进货啊？