题干
I would have come to see you earlier, but I__________too busy.
A：had bee
B：were
C：wa
D：would be
答案(点此获取答案解析）
C
A：had bee
B：were
C：wa
D：would be
小了油门，使汽车的功率立即减小一半，并保持该功率继续行驶，到t2时刻汽车又开始做匀速直线运动，整个过程中汽车所受的阻力不变。则在t1t2的这段时间内：