Mother's day is just round the cornen.I want to buy a present for my mother,one that is useful but not espensive.

问题描述:

Mother's day is just round the cornen.I want to buy a present for my mother,one that is useful but not espensive.
It seems that the news that her husband had an accident was ture.
one和news同样有同位语从句修饰,为什么one前无定冠词而news前有?

第一句中的one 是不定代词,也就是说这个礼物是不确定的,只要有用并且不要太贵就可以了.
第二句中的news是确定的,即她丈夫出事故的消息,因此要加the