单选 The two boys are playing football.And there's __boy .He is sleeping.

问题描述:

单选 The two boys are playing football.And there's __boy .He is sleeping.
A third B a third
为什么?

选B
third在这是修饰boy用的,boy是可数单数名词,所以还需要加一个冠词a或者the
(你记住可数名词单数前面要么要加a,要么加the)