加速
The speed limit on this road is 70 mph. 这条路的车速限制是每小时70英里。
He was fined for speeding to the tune of 200. 他因超速行车被罚款达 200 英镑。
The acceleration is positive if the speed is increased, negative if speed is decreased. 速度增加的加速度为正加速度，速度减少的加速度为负加速度。
The speed limit is 40 miles per hour. 规定的最高时速为40英里。
The cruiser's speed is 50 miles per hour. 巡洋舰的速度每小时有50海里。
They've speeded up production of the new car. 他们加快了新汽车的生产。
The train soon speeded up. 火车不久就加快了速度。
