1) 代词each和由every, some, no, any等构成的复合代词作主语，或主语中含有each, every, 谓语需用单数。

　　Each of us has a tape-recorder.

　　There is something wrong with my watch.

　　2) 当主语是一本书或一条格言时，谓语动词常用单数。

　　The Arabian Night is a book known to lovers of English.

　　天方夜谭是英语爱好者熟悉的一本好书。

　　3) 表示金钱，时间，价格或度量衡的复合名词作主语 时，通常把这些名词看作一个整体，谓语一般用单数。

　　Three weeks was allowed for making the necessary preparations.

　　Ten yuan is enough.