a number of 意思是“一些,若干”(= some),后接可数名词复数或代词,谓语动词用复数形式。
the number of…意思是“……的数字/数目”,介词of同其后名词构成介词短语,修饰the number.当它作主语时,谓语动词用单数。
Two significant constants have been found in a number of research studies.
若干研究已经发现了两个重要常量。
The research begs a number of questions.
研究绕过了一些问题。
The number of business failures has risen
企业倒闭的`数量增加了。
The number of independent firms decreased from 198 to 96
独立公司的数量从198个减少到了96个。