Many _______ of years later, the first e
题型：选择题
问题：
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
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