Most of the manipulators that change the format state provide set/unset pairs;one manipulator sets the format state to a new value and the other unsets it, restoring the normal default formatting.

• 大多数改变格式状态的操纵符提供设置／复原对，一个操纵符将格式状态置为新值而另一个进行复原，恢复常规默认格式。