A:世袭制
B:分封制
C:禅让制
D:宗法制
Some exchange students _______ with their host families this time yesterday.
( x2 y3-9x y5+8y2)÷y2
如图是某同学整理的丝绸之路资料卡片。其中表述错误的是丝绸之路的( )