问题如下：
“If news reaches the market that the price of oil will almost certainly increase by 20% in three months, the price will increase immediately. If news reaches the market that the price will almost certainly decrease by 20% in the next three months, the price does not necessarily decrease immediately.” Discuss this statement.
解释：
If oil prices are expected to increase sharply, speculators will buy oil and store it. This means that the price will rise until the financing cost plus the storage cost equals the expected profit. If oil prices are expected to fall sharply, there is no similar trade involving spot oil because those who hold oil in inventory need it to feed their refineries.
老师你好，题目和答案的意思能明白，结合到讲义里，这道题考察的知识点是什么？谢谢
