老师将109个香蕉平均分给4个同学,每人分几个?还剩几个?验算一下。
如图,AB为⊙O的直径,C、D为⊙O上不同于A、B的两点,∠ABD=2∠BAC,过点C作CE⊥DB,垂足为点E,直线AB与CE交于点F.
(1)求证:CF为⊙O的切线.
(2)当∠CAB=多少时,从点A、C、F、D为顶点的四边形是菱形.
Everyone would prefer to improve the________of their life by taking part in all kinds of activities.
下列直接体现我国社会主义性质的经济制度是 ( )