谓语受主语支配，它必须在人称和数等方面与谓语保持一致。
语法形式上一致
单数的名词、代词、动词不定式、动名词短语或从从句作主语时，谓语动词用单数。
What I hate most is telling lies.
To become a doctor is his ambition.
Whether she comes or not is of no matter
what引导的'从句作主语，如果它后面的表语是复数形式，谓语动词亦可以用复数。
What I said is right.
What we need badly here are doctors.
由and连接并列主语时：
Swimming in the summer and skating in the winter are my hobbies
In the city are to be found both the most renowned scholar and the scoundrels
a block and tackle;the needle and thread;brandy and soda;sale and water;law and order;a cup and saucer; the ebb and flow ; the rope and pulley
watch and chain;soap and water;etc。
There is my watch and chain on the dressing-table.
若and后面的名词前有冠词或物主代词修饰，谓语动词用复数形似。
The bread and the butter are on sale.
由and连接的并列单数主语前有each, every, no , many a 等修饰时，谓语动词用单数形式。