问题如下：
Suppose there is an order-driven system that can hide orders, here are four sell orders for the same stock, currently in the system's limit order book. In accordance with the usual common order precedence hierarchy, which of the following orders will have trading precedence？
选项：
A.Order I (time of arrival of 10:02:01).
B.Order II (time of arrival of 10:02:08).
C.Order III (time of arrival of 10:03:04).
解释：
Order III (time of arrival of 10:03:04) has precedence in this transaction. According to the priority of the transaction,first to follow the principle of price priority.In accordance with this principle,sell order II, III, and IV get precedence over order I. The second principle is display priority at a given price, orders III and IV have priority of order transaction because order II is a hidden order. The third principle is time priority at the same price and display status,order III takes precedence over order IV in the transaction.
请问hidden order是在讲义第几页讲的，是个什么概念？谢谢。
