(1)表示确切数量使用下面结构

基数词+hundred +名词复数

There are eight hundred students in the school.

基数词+thousand +名词复数

There are eight thousand students in the university.

基数词+million+名词复数

There are eight million people in the city.

基数词+billion+名词复数

There are 1.3 billion people in China.

(2)表示模糊(不确切)数量使用下面结构

hundreds of +名词复数

There are hundreds of people in the park.

thousands of+名词复数

There are thousands of people in the square.

millions of +名词复数

There are millions of stars in the sky.

billions of +名词复数

There are billions of stars in the sky.

    hundred, thousand, million这三个词用复数和后接of的用法：

    1. hundred, thousand, million这三个词用单数形式时，后面可以直接接复数名词，不能接of；在这三个词前面可以加不定数量词（如many /several / a few）或者基数词。

    2. hundreds of, thousands of, millions of 这三个短语中，of 前面的名词必须用复数形式，of后面接复数名词。在这三个短语前面可以加不定数量词（如many /several / a few），但是不能加基数词。