A:①
B:①②
C:①②③
D:①②③④
以初速度v0水平抛出一个物体,经过时间t物体的速度大小为v,则经过时间2t,物体速度大小的表达式正确的是( )
—I'm afraid I can't travel with you.—Don't worry. We'll going on vacation until you're better.