点A（-2，6）与点B关于原点O对称，则点B的坐标为（ ）。
（2，-6）
胶带大量粘煤会导致的后果是什么？
(74) is NOT served by building a prototype.
A．It takes the place of the final system
B．It is used as the foundation of the larger projects
C．It assists in estimating the cost of the project
D．It assists in gathering software requirements
