空闲的

Weekends are free, too.

周末也是空闲的。

How do you spend your leisure?

你是怎样消磨空闲时间的?

Hot-potato router can arbitrarily choose one free output port without waiting,but it has the problem of livelock.

热土豆路由在路由器从，任意选择一个空闲的口进行发送，但却有活。