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.
A．trying B．checking C．testing D．coding
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 The maximum number of data that can be expressed by 8 bits is（）.
单项选择题 Every valid character in a computer that uses even（）must always have an even number or 1 bits.
