Many of years later, the first extremely small plants began to appear on the surface of the water.
A. millions
B. million
C. million of
D. millions of
网友回答
(答案→)A. millions
B. million
C. million of
D. millions of
解析：本题考查数词。Millions of上百万的，许许多多的;因为横线后面有of，排除D项。句意：上百万年之前，第一个极其小的植物开始出现在水面上。