主谓一致：the old
名词化的形容词作主语时要看主语的具体情况。
一. 看作复数
The wounded were sent home.
伤员被送回家。（指一批人，动词用复数。）
The old are taken good care of here.
这儿的老人受到很好的照顾。（一批人）
二. 看作单数
The true is to be distinguished from the false.
真假必须辨明。（抽象的概念，看成单数。）
The accused was punished to prison.
那个被告被判入狱。（一个人）
主谓一致：two years
时间、金钱、路程的名词
虽是用复数形式作主语，谓语动词仍然要用单数形式。
Two years is enough.
两年就够了。
A hundred miles is a long distance.
一百英里是一段很长的距离。
主谓一致：percent
分数和百分数的词作主语时，以“of 短语”中的名词为判断标准。
Thirty percent of the grain is used to feed animals.
百分之三十的粮食用来饲养牲口。
Ninety percent of the smokers are male.
百分之九十的吸烟者是男性。
主谓一致：each
以下列不定代词作主语的句子谓语动词用单数：
either, neither, each, one, the other, another, anybody, anyone, anything,
somebody, someone, something, everybody, everyone, everything, nobody,
no one, nothing（含有单数意义的不定代词）
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Neither of those men is wrong.
那两个人都没有错。
Each of the books costs ten dollars.
每一本书花费10美元。
Somebody is using the phone.