名詞 rapid:

1. a part of a river where the current is very fast

形容詞 rapid:

1. done or occurring in a brief period of time
2. characterized by speed; moving with or capable of moving with high speed
   同義詞：speedy

1. With the rapid economical development, China's position on the international stage is getting more and more important.
   隨著經(jīng)濟迅速發(fā)展，中國在國際舞臺上的地位變得愈來愈重要了。
2. The student is showing rapid progress in his studies.
   這個學生學習上進步很快。
3. The rapid spread of the disease is alarming the medical authorities.
   這種疾病的迅速蔓延使醫(yī)療當局感到憂慮不安。
4. The intercession has made a rapid progress.
   調(diào)解已經(jīng)取得了很大的進展。
5. A tremulous or pulsating effect produced in an instrumental or vocal tone by barely perceptible minute and rapid variations in pitch.
   顫音一種顫動或振動效果，由可察覺的微小迅速的音階變化在聲音或樂器的調(diào)子中產(chǎn)生的
6. Loud or rapid talk; chatter.
   聊天大聲急促的談話; 聊天
7. Childhood is a period of rapid growth.
   幼年是生長迅速的時期。
8. He made rapid progress in his studies.
   他學習上進步很快。

rap.id

adj.（形容詞）
rap.id.er,rap.id.est
Moving, acting, or occurring with great speed; swift.See Synonyms at fast
迅速的：以極高速度運動，行動或發(fā)生的；飛快的參見 fast
n.（名詞）
An extremely fast-moving part of a river, caused by a steep descent in the riverbed. Often used in the plural.
急流，湍灘：由于河床傾斜下降而形成的流動極快的河流的一部分，常用復數(shù)

來源：
Latin rapidus
拉丁語 rapidus
from rapere [to seize] * see rep-
源自 rapere [抓住] *參見 rep-

【引伸】
rapid.ity
rap.idly
adv.（副詞）