表示路程的s是英文单词speed；表示速度的v是英文单词velocity。speed的英式读法是[spid]；美式读法是[spid]。作名词时意思是速度；迅速。作动词时意思是加速；急行。
例句
They were travelling at a speed that was double the legal limit.
他们正以两倍于法定限速的速度行驶。
The police are advising motorists to reduce speed because of the fog.
由于有雾，警察告诫驾车者减慢速度。
