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(jì)迅速發(fā)展，中國(guó)在國(guó)際舞臺(tái)上的地位變得愈來愈重要了。
2. The student is showing rapid progress in his studies.
   這個(gè)學(xué)生學(xué)習(xí)上進(jìn)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(dāng)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(jìn)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(dòng)或振動(dòng)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(zhǎng)迅速的時(shí)期。
8. He made rapid progress in his studies.
   他學(xué)習(xí)上進(jìn)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(yùn)動(dòng)，行動(dòng)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(dòng)極快的河流的一部分，常用復(fù)數(shù)

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

【引伸】
rapid.ity
rap.idly
adv.（副詞）