A:③④
B:①②③④
C:①②③
D:①④
“不登高山,不知天之高也;不临深溪,不知地之厚也。”这表明( )。
—_______ do you know so much about the cartoon?
—I got the information by surfing the Internet.
已知双曲线x2cos2θ-y2sin2θ=1(π2<θ<π)的右焦点为F,P是右支上任意一点,以P为圆心,PF长为半径的圆在右准线上截得的弦长恰好等于PF,则θ的值为( )