如图所示,在外力作用下某质点运动的v﹣t图象为正弦曲线.从图中可以判断( )
A:在0﹣t1时间内,外力做正功
B:在0﹣t1时间内,外力的功率逐渐增大
C:在t2时刻,外力的功率最大
D:在t2﹣t3时间内,外力做的总功为零
________ my father _______ my mother is able to drive a car. However, they are going to buy one.