据史书记载,春秋初期有诸侯国一百多个,到战国初期仅剩下十几个,“诸侯”是随着哪一制度产生的( )
A:禅让制
B:世袭制
C:郡县制
D:分封制
Police: What's in your wallet? Owner: There some money and two tickets for today's e-sports competition.
已知两不共线向量a→=cosα,sinα,b→=cosβ,sinβ,则下列说法不正确的是 ( )