In our city middle school students want to work as a teacher in the future.A. thousandB.

问题补充：

In our city, middle school students want to work as a teacher in the future.

A. thousand

B. thousand of

C. thousands of

D. two thousand of

答案：

A. thousand

B. thousand of

(答案→)C. thousands of

D. two thousand of

解析：hundred 、thousand这些量词前面有数字的，如two thousand ，thousand后面绝不能加s;，表示具体数字。如果后面加s，前面则不能有数字，表示一个模糊地数字概念。

根据题意这里中学生数量是概数,故选C,成千上万的.