There are three sheep on the farm.A. thousandB. thousandsC. thousand ofD. thousands of

问题补充：

There are three sheep on the farm.

A. thousand

B. thousands

C. thousand of

D. thousands of

答案：

A. thousand

B. thousands

(答案→)C. thousand of

D. thousands of

解析：此题考查名词的量。确切数量常用数词+hundred/thousand/million/billion+名词的复数形式；不确切数量常用hundreds/thousands/millions/billions + of+名词的复数形式.