问题如下：
“In theory tailing the hedge involves adjusting the number of contracts used with the passage of time.” Explain this statement.
选项：
解释：
Because futures contracts are settled daily, a hedge using futures contracts is actually a series of one-day hedges. In theory, the hedge ratio changes because the asset price and the futures price change, and because a discount factor is necessary to account for the time dif-ference between each one-day hedge and the end of the life of the hedge. In practice, it is often the case that the hedge ratio is calculated throughout the life of the hedge using the initial values of the asset price and the futures price, and the effects of the discount factors are ignored.
可以解释一下题目和解答是什么意思的？看不太懂。
