有一读者问：《学英语》报上曾有下面两句话：
(1)Two-thirds of water in the river has been polluted.
(2)Three-fourths of the flour are produced in this flour factory.
为什么句（1）用单数动词has,句（2）却用复数动词are?
“分数+of+名词”用作主语时，其后动词的单复数一般应由名词的数念而定，如上述句（1）中的名词water是不可数名词，故其后的动词应用单形has。名词如是可数复形名词，其后则应用复数动词，如：
(3)Two-thirds of people were illiterate.
但有时动词的数形并不决定于名词，而却从分数的数形出发，如：
(4)Three-fourths of anybody's fame are mere suggestion. （这里的复形three-fourths与复形动词are一致）
上述句（2）之所以用复数动词即是由于其主语是复形的缘故。至于“分数+of+名词”后的动词应取决于名词的数，还是取决于分数的数，那就决定于说（写）话人的主观态度了。
