能不能补充介绍下什么时候适合trailing PE？

问题如下：

1. Based on the information in Exhibit 1, the most appropriate price-to-earnings ratio to use in the valuation of Delite is closest to:

选项：

18.71.

19.04.

24.44.

解释：

A is correct.

The forward P/E ratio should be used given the recent significant acquisition of the water bottling company. Since a major change such as an acquisition or divestiture can affect results, the forward P/E, also known as the leading P/E or prospective P/E, is the most appropriate P/E to use for Delite. Earnings estimates for 2011 should incorporate the performance of the water bottling company. The forward P/E is calculated as the current price divided by the projected earnings per share, or $65.50/$3.50 = 18.71.