This, they said, helps guard against the aging process.
他们说，这有助于防止衰老过程。
2
That is, a channel guard is ready if and only if the process at the other end of the channel has output to it and this data has not yet been input by this process.
也就是说，只有在通道另一端的进程已经输出数据，而该数据还没有被进程输入的时候，警卫才就绪。
3
In the specific context of JCSP, an abstract class called Guard is provided, which must be subclassed by event objects that are competing for selection by a process.