这几个词的以下用法应该值得注意：

1.当这些词与具体数字连用时，通常不加复数词尾-s，也不后接介词 of。如：

Down fell a dozen apples. 掉下来10来个苹果。

He has lived here for two score years. 他已在这儿住了40年。

He was paid five hundred dollars. 他们付给了他500美元。

His wages were eight thousand pounds a year. 他的工资是每年8,000英镑。

About three million workers were on strike. 参加罢工的大约有300百万工人。

几点说明：

(1) 有人认为dozen和score与具体数字连用时有时也接 of，但比较而言，dozen后很少接介词of，而score后则接不接介词of 均可以。

(2) 指特定人或物中的一部分时，其后必须用介词of——此时of后接的要么是人称代词（如us, them），要么是带有特指限定词（如the, my, our, these, those等）的名词。如：

About two hundred of them are students. 他们当中大经有200人是学生。

I want three dozen of these eggs. 这种鸡蛋我要3打。

About three thousand of the workers were wounded. 工人中大约有3,000人受了伤。

(3) 当 million 用作中心词（即其后不接名词或数词）时，有时也可带复数词尾-s。如：

The television audience aggregated 30 millions. 电视观众合计达3,000万人。

2.当这些词不与具体数字连用，而是表示不确定的泛指数时，则不仅要加复数词尾-s，而且要后接介词of，然后才能接名词。如：

The city has dozens of bus lines. 那座城市有好几十路公共汽车。

Scores of volunteers offered to help. 很多志愿者主动提供帮助。

We have been there hundreds of times. 那儿我们去过数百次。

Thousands of students entered the contest. 数千名学生参加了这次比赛。

His investments amount to millions of dollars. 他的投资额达几百万美元。

几点说明：

(1) 为加强语语气，有时可用tens of thousands, hundreds of thousands, thousand and millions等。如：

Hundreds of thousands are homeless. 几十万人无家可归。

The dollar revenues each year were undoubtedly in the tens of millions. 每年美元税收无疑数以千万计。

(2) 若其后不出现名词，则不用介词 of。如：

It cost thousands. 买这东西用了好几千呢。

There are hundreds begging in the streets. 街上有数以百计的乞丐。

Her acting has given pleasure to millions. 她的表演给千百万人带来娱乐享受。

3.当这些词与 a few, several, many 等数目不很具体的词连用时，带不带复数词尾 -s 均可，但是注意：若不带复数词-s，则通常不接介词of；若带复数词尾-s，则其后必须要有介词of。如：

油井向下延伸了数百英尺。

正：The oil well extended several hundred feet in depth.

正：The oil well extended several hundreds of feet in depth.

误：The oil well extended several hundreds feet in depth.

当然，若其后不接名词，则自然不能接介词of。如：

The devaluation of the pound has put our estimates out by several thousand(s). 英镑一贬值使我们的估计数差了几千镑。

摘自：http://www.yygrammar.com/Article/201503/3850.html