问题补充:
There are birds there in the sky.
A. Million of
B. five millions of
C. millions of
D. five millions
答案:
A. Million of
B. five millions of
(答案→)C. millions of
D. five millions
解析:句意:天上有成千上万的鸟。Millions of成千上万的,million要用复数;但在具体数字中例如five million五百万,million不用复数,故选C。