A:F甲=F乙,ρ甲=ρ乙
B:F甲=F乙,ρ甲<ρ乙
C:F甲<F乙,ρ甲=ρ乙
D:F甲>F乙,ρ甲>ρ乙
—Catherine, I have cleaned the room for you.
— Thanks. You _______ it. I could manage it myself.
下列关于鸟类飞行特点的叙述,错误的是( )