带确定数量词的名词词组作主语时的主谓一致
1、当主语是表示数目、时间、重量、距离等的复数名词时，如果该名词所表示的数量看作一个整体，其后的动词用单数。
Four years is too long for me to wait.
Sixty miles is a short run in a car.
2、当主语是表示数目、时间、重量、距离等的复数名词时，如该名词所表示的数量看作单个个体，其后的动词用复数。
The past three weeks were the hardest time in his life.
Hundreds of buildings were put up in the city last year.
3、当主语为“分数或百分数+of+名词”时，其后的动词形式依照of后名词的单复数形式来定。
Thirty percent of the oil in that country is imported.
Ten percent of the eggs have gone bad.
4、当主语为sheep,fish,deer,aircraft,means,steelworks等单数与复数同形的词时，动词的形式以名词单、复数意义为准。
Three aircraft are reported missing.
Ten fish have been caught today.