million是百萬的意思，billion是十億的意思。
?million
1、(abbr. m)?壹百萬?
1 000 000
a population of half a million
五十萬人口
tens of millions of dollars
數千萬元
It must be worth a million (= pounds, dollars, etc.)?
它壹定值壹百萬。
a, one, two, several, etc. million 時，million 後面不加 s。若前面沒有數目或數量，可用 millions (of ...)。million 和 millions 均用復數動詞，指明金額除外：Four million (people) were affected. Two million (pounds) was withdrawn from the account.
2、a million
(or?)?millions (of…)
(informal)?大量?
a very large amount
I still have a million things to do.
我還有很多很多的事情要做。
There were millions of people there.
那裏人山人海。
He made his millions (= all his money) on currency deals.
他的萬貫家財都是通過外匯交易得到的。
billion
1、(abbr. bn)?十億?
1 000 000 000; one thousand million
Worldwide sales reached 2.5 billion.
全球銷售額達到了25億。
half a billion dollars
五億元
They have spent billions on the problem (= billions of dollars, etc.) .
他們花了幾十億元解決這個問題。
There are more examples of how to use numbers at the entry for hundred . 說 a, one, two, several, etc. billion 時， billion後面不加s。若前面沒有數目或數量，可用billions (of...)。除非指金額，billion和billions均用復數動詞：預計全世界將有20億人觀看這場比賽。從該賬戶提取了20億元。更多數詞用法示例見hundred詞條。
2、a billion
(or?)?billions
(informal)?數以十億計；大量?
a very large amount
Our immune systems are killing billions of germs right now.
我們的免疫系統正在殺死數以十億計的細菌。
3、(old-fashioned,?BrE)?壹萬億?
1 000 000 000 000; one million million