5.以s 结尾但表示学科、国家、机构、书籍、报刊等名称作主语时谓语用单数。
Eg:maths,physics，Swiss，the United states
Twenty years _________ (pass) since he left his hometown.(has passed)
6.表示时间、距离、金钱、等复数名词作主语,表达一个整体概念时谓语用单数。
Anything _________（be） possible.(is)
7.由any-,some-,no-和-one,-thing,-body等所构成的不定代词作主语时谓语用单数。
Collecting stamps _________（be）what he likes.(is)
Whatever was left _________（be）taken away.(is)
