多线程是为了同步完成多项任务，不是为了提高运行效率，而是为了提高资源使用效率来提高系统的效率。线程是在同一时间需要完成多项任务的时候实现的。-Multithreading is to synchronize the completion of many tasks, not to improve the efficiency, but to improve the efficiency of resource use to improve the efficiency of the system