Football is so exciting that people in the world play it. A. million of B. millions of C.

问题补充：

Football is so exciting that people in the world play it.

A. million of B. millions of C. two millions of

答案：

解析：考察数词。Million和数词连用表示具体数字，用原形。和介词of连用表示概数，用复数形式。句意：足球是如此令人兴奋，因此世界上有无数的人踢。结合语境可知本句表示概数，故选B。