rapidly,soon,quickly,fast之间有什么区别？

fast,rapid,quick,这组词都有“快的”意思。
fast和rapid虽然有时可以互换使用，但它们有差异，fast强调物体进行相对运动。如a fast horse, a fast train. fast可做副词
The winning car reached a speed of forty miles——much faster than any of its rivals.
获胜的那辆车的时速达到40英里——比它的任何竞争者要快得多。
Letters will cost a little more, but they will certainly travel faster.
寄信要多花一点钱，但无疑书信走得会快一些。
而rapid只表示运动着的物体或事物的本身状况，并不涉及单位时间内所越过的距离。如：rapid work, rapid current, rapid progress
It is a rapid river.
那是一条湍急的河。
Working rapidly in the darkness, he soon changed into the man's clothes.
他在黑暗中动作迅速，很快换上了死者的衣服
quick修饰事情发生得快，占用的时间少，也不涉及速度。如：quick thinking, a quick temper
Roy acted quickly and drove the bus straight at the thieves.
罗伊的动作迅速，开着公共汽车直向小偷扑去。
…the forest authorities ordered several tons of a special type of grass-seed which would grow quickly.
森林管理当局订购了好几顿特殊类型的速生草籽。
…they quickly dragged the drunk to safety.
他们迅速地把醉汉拖到安全处。

rapidly和quickly没什么区别，都是指动作等迅