“齐人”、“鲁人”、“楚人”这种表述，逐渐让位于以行政区划为籍贯的表述，造成这一变化的制度因素是 A.分封制 B.宗法制
加成反应也是有机化学中的一类重要的反应类型，下列各组物质中不能全部发生加成反应的是（ ） A．乙烷、乙烯 B．乙烯、乙炔 C．氯乙
The Artist and the Beggar (1) An artist was coming home by train one day. He hadn’t much money but was very kind. He gave his last few coins(2) to a beggar, but he saw another one,
下列说法正确的是（ ） A． 掷一枚硬币，正面一定朝上 B． 某种彩票中奖概率为1%，是指买100张彩票一定有1张中奖 C． 旅客上飞机前的安检
Nine out of 10 people have run up unsecured debt and many fear they will never be able to pay back what they owe, a survey has claimed. Around 89% of people aged between l|8 and 35 said t
一个基因型为AaBb的精原细胞产生AB型配子的几率为（ ） A．0 B．25% C．50% D．不能确定
如图：在直角坐标系xoy中，设椭圆C：=1（a＞b＞0）的左右两个焦点分别为F1、F2．过右焦点F2与x轴垂直的直线l与椭圆C相交，其中一个交点为． （1）求椭
的最小值是_________.