thousand

There are two thousands students in the school.→There are two thousand students in the school.

在数字后，thousand 应保持单数形式，不加 s。

I have thousand books at home.→I have a thousand books at home.

表示‘一千’时，应使用‘a thousand’或‘one thousand’，不能省略冠词。

Thousand of people attended the concert.→Thousands of people attended the concert.

表示‘成千上万’时，应用复数形式 thousands of，而不用单数 thousand。