问题补充：
There are stars in the sky and you can see them at night.
A. thousand of
B. two thousands
C. thousands of
D. two thousands of
答案：
A. thousand of
B. two thousands
(答案→)C. thousands of
D. two 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:天空中有无数的星星,在夜晚你能看见他们.结合语境可知选C.
