謂語受主語支配，它必須在人稱和數等方面與謂語保持一致。
語法形式上一致
單數的名詞、代詞、動詞不定式、動名詞短語或從從句作主語時，謂語動詞用單數。
What I hate most is telling lies.
To become a doctor is his ambition.
Whether she comes or not is of no matter
what引導的'從句作主語，如果它後面的表語是複數形式，謂語動詞亦可以用複數。
What I said is right.
What we need badly here are doctors.
由and連接並列主語時：
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後面的名詞前有冠詞或物主代詞修飾，謂語動詞用複數形似。
The bread and the butter are on sale.
由and連接的並列單數主語前有each, every, no , many a 等修飾時，謂語動詞用單數形式。