已知：在等腰梯形ABCD中，AD∥BC，对角线AC⊥BD，AD=3cm，BC=7cm，则梯形的高是（ ）cm。
5
Take an umbrella to ______you from the rain, which may ___you from taking a walk.
A．protect; stop
B．protect; protect
C．prevent; protect
D．prevent; keep
末本
