重介质选煤的基本原理是什么？
Refer to the exhibit. At the end of an RSTP election process, which access layer switch port will assume the discarding role?（） ["Switch3, port fa0\/1","Switch3, port fa0\/12","Switch4, port fa0\/11","Switch4, port fa0\/2","Switch3, port Gi0\/1","Switch3, port Gi0\/2"]
简述8259采用非自动结束方式工作时，中断服务程序为何要发送EOI命令给8259？何时发送？
旋流器内任意点的速度可以分解为哪三种速度？
新生班级管理的准备工作主要有哪些内容？
水运的优缺点主要表现在什么地方？
