Every year people go to visit their factoryA. a thousand ofB. thousandsC. thousand ofD. t

问题补充：

Every year, people go to visit their factory

A. a thousand of

B. thousands

C. thousand of

D. thousands of

答案：

A. a thousand of

B. thousands

C. thousand of

(答案→)D. thousands of

解析：英语中数词表示概数时，后面加s，和介词of搭配使用。用原形时表示具体数字和数词搭配使用。句意：每年，成千上万的人参观这家工厂。结合语境可知本句描述的是大概是数字，故选D。