1 並列結構作主語時謂語用復數
Reading and writing are very important.
2 主謂壹致中的（就近原則）
當there be 句型的主語是壹系列事物時，謂語應與最鄰近的主語保持壹致.
There is a pen,a knife and several books on the desk..
There are twenty boy-students and twenty-three girl-students in the class.
3 謂語動詞與前面的主語壹致 （就前原則）
當主語後面跟有with,together with,like,except,but,no less than,as well as 等詞引起的短語時，謂語動詞與前面的主語壹致.
The teacher together with some students is visiting the factory.
He as well as I wants to go boating.
4 謂語需用單數
1) 代詞each和由every,some,no,any等構成的復合代詞作主語，或主語中含有each,every,謂語需用單數.
Each of us has a tape-recorder.
There is something wrong with my watch.
2) 當主語是壹本書或壹條格言時，謂語動詞常用單數.
The Arabian Night is a book known to lovers of English.
<壹千零壹夜>是英語愛好者熟悉的壹本好書.
3) 表示金錢，時間.距離.價格或度量衡的復合名詞作主語時，通常把這些名詞看作壹個整體，謂語壹般用單數.(用復數也可，意思不變.)
Three weeks was allowed for making the necessary preparations.
Ten yuan is enough.