preemptive schedule的用法和樣例：
例句
- What is the difference between preemptive scheduling and time slicing?
搶先調度與分時調度有何不同？ - Under preemptive scheduling, the highest priority task executes until it enters the waiting or dead states or a higher priority task comes into existence.
採用搶先調度方式時，具有最高優先順序的任務先執行直到它進入等待或僵死狀態，或者是有更高優先順序的任務產生。
