Please take some photos the pandas and send them to me email.
A:of; in
B:of; by
C:by; in
D:to; by
世界上最长的山脉是( )
已知A1,A2为椭圆x24+y2=1的左右顶点,在长轴A1A2上随机任取点M,过M作垂直于x轴的直线交椭圆于点P,则使∠PA1A2<450的概率为( )