________ years ago, coal came from trees and other plants that grew on earth.
A.Million of
B.Million
C.Millions of
D.Millions
网友回答
C解析这里考查学习对million，thousand，hundred这类词的使用。我们知道：“hundred”，“thousand”，“million”它们前面若有数词时，它们不能加s，即以单数形式出现；如果前面没有任何数词，则必须加S，且经常与of连用。例如：Millions of people are holding a meeting on the square.几百万人在广场上开会。Five million sets of books are being printed.500万套书正在付印。Some millions of workers were on strike.好几百万人罢了工。Some two million fishes died in the river.大约两百万条鱼死在河里了。