在班级管理中，学生既是班级管理的客体，又是班级管理的主体。
足球比赛中，防守一方踢或触球，使球的整体从本方端线越出时，应由对方队员踢罚（）恢复比赛。 ["任意球","角球","球门球","界外球"]
Which three statements about bidirectional PIM are true？（） ["Traffic for a bidirectional group flows along the one shared tree and simultaneously utilizes multiple paths in a redundant network topology","It does not require any traffic signaling in the protocol","Membership to a bidirectional group is signaled using explicit Join messages","It maintains source-specific forwarding state","It reduces memory， bandwidth， and CPU requirement"]
排气消声器的功用是什么？
how many neighbor commands required for establish ibgp peers in 4 routers？
唐、明、清四朝封建经济迅速恢复和发展的共同原因是什么？其经济发展又各有何特点？这几个朝代政策的调整有什么作用？为什么最终又导致土地兼并严重的恶果？
