一、a number of, the number of

a number of 意思是“許多”，相當于a lot of ; the number of意思是“……的數目,……的數量”，當它作主語時，謂語動詞用單數形式。

A number of students like playing computer games.

許多學生喜歡玩電腦游戲。

The number of the students is about 1500 in our school.

我們學校學生的人數大約是1500。

二、基數詞變序數詞助記歌。

基變序，有規律，末尾加上th;一、二、三特殊記，八加h ，九去e ，ve要用f替;以e結尾變ie，后跟th莫忘記。要想表示幾十幾，只變個位就可以。

特殊變化：one—first ,two—second ,three—third ,five—fifth ,

nine—ninth ,twelve—twelfth ,forty—fortieth ,

eight-nine—eighty-ninth

三、概數表達法

數詞+hundred/thousand/million/billion+名詞復數

hundreds/thousands/millions/billions of+名詞復數

例1

1. ______ people go swimming in summer in Dalian.

A、Thousands B、Thousand of C、Thousands of D、Thousand

2. ______ the students will take part in this English speech contest.

A. Two hundred of B. Two hundreds of C. Hundreds of D. Hundred of

答案：C；A