A:①②
B:①③
C:②④
D:③④
请根据图象回答下列问题:
将左右两部分搭配,使其成为通顺的句子。
①Is she in the study?____ A. It's on the desk.
②Is this your bedroom?____ B. No, they aren't.
③Where's my pen?____ C. No, it isn't.
④Are they on the chair?____ D. Yes, she is.
⑤Where are my books?____ E. They are on the bed.
如图,已知椭圆C的中心在原点O,左焦点为F1(﹣1,0),左顶点为A,且F1为AO的中点.
(1)求椭圆C的方程;
(2)若椭圆C1方程为:x2m2+y2n2=1m>n>0,椭圆C2方程为:x2m2+y2n2=λ,则称椭圆C2是椭圆C1的λ倍相似椭圆.已知C2是椭圆C的3倍相似椭圆,若椭圆C的任意一条切线l交椭圆C2于两点M,N,试求弦长|MN|的最大值.
眼睛中的“黑眼球”和“白眼球”分别是指( )
已知a→=1,2,b→=x,1且a→+2b→∥2a→-b→,则x为 ( )