1） 在代詞what, which, who, none, some, any, more, most, all等詞的單復數(shù)由其指代的詞的單復數(shù)決定。
　　 all is right.　　　 (一切順利。)
　　 all are present.　　(所有人都到齊了。)

2） 集體名詞作主語時，謂語的數(shù)要根據(jù)主語的意思來決定。如family, audience, crew, crowd, class, company, committee等詞后用復數(shù)形式時，意為這個集體中的各個成員，用單數(shù)時表示該個集體。
　　 his family isn't very large.　　他家不是一個大家庭。
　　 his family are music lovers.　他的家人都是音樂愛好者。
　 但集合名詞people, police, cattle, poultry等在任何情況下都用復數(shù)形式。
　　are there any police around?

3）有些名詞，如variety, number, population, proportion, majority 等有時看作單數(shù)，有時看作復數(shù)。
　a number of +名詞復數(shù)+復數(shù)動詞。
　the number of +名詞復數(shù)+單數(shù)動詞。
　a number of books have lent out.
　the majority of the students like english.