题干
students English well, the teacher tries to speak English in class very often.
A：Teaching
B：Taught
C：To teach
D：Teach
答案(点此获取答案解析）
C
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：
