某同学设计渗透装置如右图所示(开始时状态),烧杯中盛放有蒸馏水,图中猪膀胱膜允许单糖透过。倒置的长颈漏斗中先装入蔗糖溶液,一定时间后再加入蔗糖酶。该实验过程中最可能出现的是
A:漏斗中液面开始时先上升,加酶后即下降
B:漏斗中液面先上升,加酶后继续上升,然后下降
C:加酶前后,在烧杯中都可以检测出蔗糖
D:加酶后可以在烧杯中检测出葡萄糖、果糖和蔗糖酶
Say “I’m sorry.” When you a mistake.
已知对称中心在原点的椭圆的一个焦点与圆x2+y2﹣22x=0的圆心重合,且椭圆过点(2,1).
(1)求椭圆的标准方程;
(2)过点P(0,1)的直线与该椭圆交于A,B两点,O为坐标原点,若AP→=2PB→,求△AOB的面积.
A dog has a piece(片) of meat in his mouth. He sees himself(他自己) in the water. He thinks it is another dog. That dog has a piece of meat in his mouth,too. He wants to get(得到) his meat. Then he can have two pieces. He opens his mouth to bark(吠叫) and his meat goes down into(在……里面) the water.
雷锋说:“一滴水只有放进大海里才永远不会干涸,一个人只有当他把自己和集体事业融合在一起的时候才最有力量。”这句话说明( )
①集体不能离开个人
②个人不能离开集体
③个人只有依靠集体才能有无穷的力量
④集体只有依靠个人才能有无穷的力量