单项选择题 若某二叉树的先序遍历序列和中序遍历序列分别为PBECD、BEPCD，则该二叉树的后序遍历序列为（）。

单项选择题 GIF files are limited to a maximum of 8 bits/pixel，it simply means that no more than 256 colors are allowed in（）.

单项选择题 integration（）is the process of verifying that the components of a system work together as described in the program design and system design specifications.