It wasn't easy having my friends talk about their freshman years____ I wasn't a part of.
A:whom
B:when
C:that
D:what
希腊历史学家希罗多德说,克利斯提尼“领着人民参与政治”。克利斯提尼改革中符合这一评述的是( )
①按财产多寡划分社会等级 ②用10个地域部落取代原来4个血缘部落
③设立五百人会议 ④向公民发放“观剧津贴”
5×5=( )
已知一个扇形的周长是12cm,
(1)若扇形的圆心角α=300,求该扇形的半径
(2)当扇形半径为何值时,这个扇形的面积最大?别求出此时的圆心角.
依据达尔文进化论的观点,人类起源于( )