我比44大,我比23+23的和小。
A:44
B:45
C:46
D:47
指出北极村发展旅游业的优势条件,并分析北极村冬季和夏季为旅游旺季的原因。
— Why did she ______ your invitation?
— Because she had an important meeting to attend that day.
如图所示为某生态系统中的食物网,请根据图回答有关问题:
已知F1、F2分别是双曲线 x2a2−y2b2=1(a>0,b>0) 的左右焦点,A为双曲线的右顶点,线段AF2的垂直平分线交双曲线与P,且|PF1|=3|PF2|,则该双曲线的离心率是( )