地球赤道周长是4万千米,如果一飞行器以1000千米/小时的速度沿赤道近地面上空飞行一周,约需( )
如图四边形ABCD中,∠B=90º,AB=4,BC=3。CD=13,AD=12,求四边形ABCD的面积。
—Are you pleased with the result of the exam?— Not at all, I can't have _______.