there be 句型中的be 的选择规则就是“就近原则”.
       there is和there are 要看后面的主语,be动词的选择和后面紧挨着的那个主语一致。
There is a  ruler,two books and three pens in my bag .
There are two books ,a  ruler and  three
books in my bag.
There is an apple and two oranges on the table. 
there is和there are的就近原则
there is后面跟单数,there are后面跟复数,就近原则是指离后面跟谁就用谁的单复数,如,跟apples就用there are,跟an apple就用there is
there is和there are的就近原则
在there be句型中,如果"be"后的主语是由and连接的两个或两个以上的名词,那么be的形式要遵循就近原则,"be”的形式是由与它最近的那个名词来确定的。若那个名词是单数或不可数名词要用is , 是复数就用are