先看一个栗子：
Reading and writing are very important.
一般情况下，由and 连接的两个名词时,不论名词是否可数与不可数,都当成复数的主语.
注意： 当主语由and连结时，如果它表示一个单一的概念，即指同一人或同一物时，谓语动词用单数，and 此时连接的两个词前只有一个冠词。
The iron and steel industry is very important to our life.
典型例题
The League secretary and monitor ___ asked to make a speech at the meeting.
A. is B. was C. are D. were
答案B. 注： 先从时态上考虑。这是过去发生的事情应用过去时，先排除A.，C.。本题易误选D，因为The League secretary and monitor 好象是两个人，但仔细辨别， monitor 前没有the，在英语中，当一人兼数职时只在第一个职务前加定冠词。后面的职务用and 相连。这样本题主语为一个人，所以应选B。
Early to bed and early to rise makes a man healthy、weathy and wise.
早睡早起,可以使一个人健康、富有、聪明.
句子中主语是Early to bed and early to rise 早睡早起是一个统一的概念,所以用的是单数,类似的情况比如,a knife and fork 一套刀叉,也要用单数动词
大家要注意：一般情况下，由and 连接的两个名词时,不论名词是否可数与不可数,都当成复数的主语.
Water and air are necessary for human beings.
一些习惯特例除外，
比如： fish and chips ，bread and butter， knife and fork 等，看做同一个事物，后面用单数谓语。
Getting up early and going to bad early is a good habbit.
一个可数名词和一个不可数名词做主语 比如
Paper and pen are mine.
The love and care from my parents are precious for me.
在there is/are句型中,and 连接的主语,用就近原则有可能是单数或复数. 其它情况,and 连接的主语,谓语动词用复数:
There is warter and apples in the house.
There are eggs and warter in the house.