1.表示“几分之几”的词称为分数词。分数词是由基数词和序数词合成的，基数词代表分子，序数词表示分母，除了分子为1的情况外，序数词都用复数：
1/4one-fourth
2/3two-thirds
3/5three-fifths
9 3/4 nie and three-fourths (九又四分之三)
另外还有下面表示法：
1/2a(one)half
3/4three-quarters
1/4a(one)quarter
2 1/4 two and a quarter
2/3 two over three
2.分数词在句中可用作：
1)分数词作主语：
A quarter of the workers are women.
四分之一的工人是女工。
Over nine-tenths of China's inhabitants belong to the Han nationality
中国居民的十分之九以上为汉族人。
2)分数词作宾语或介词宾语：
They used one-fifth of the money for capital construction.
他们用五分之一的钱进行基本建设。
They account for one sixth of the population.
他们占人口的六分之一。
3)分数词作同位语或表语：
Some 565 million people, about two-fifths of our population, live in this area.
占我国人口五分之二的五亿六T五百万人居住在这个地区。
The crop that year was only one-third of the usual amount.
这年的收成只是正常年景的三分之一。
3.分数词作定语(a)或状语(b)：
a.It's one-twentieth the thickness of a human hair.
它相当于人头发丝的二十分之一(那么细)。
b.China is one-sixth larger than the United States.
中国比美国大六分之一。
