所谓非断定结构，简单地说就是含有非断定词项（有的语法著作称之为非肯定词）的结构。

那么非断定词项（或非肯定词）是指哪些词？其中最常见的就是 any 以及 anyone, anything, anybody, anywhere 等，另外还包括 either, at all, ever, yet 等。如果一个句子结构含有这类非断定词项（或非肯定词），那么它就是非断定结构。如：

Do you have any money? 你有钱吗？

He has never been to any foreign countries. 他从未到过国外。

Is there any remedy for this disease? 有没有治疗这种病的药？

I don’t know anybody in that town. 在那个镇上我谁也不认识。

There was no shelter within view anywhere. 举目四望不见可栖身之处。

I didn’t understand anything at all. 我一点儿也没弄明白。

I didn’t go to the meeting either. 我也没去开会。

It’s the worst play I’ve ever seen. 这是我看过的最糟糕的剧了。

I haven’t heard from her yet. 我还没听到她的消息呢。

If you ever need any help, you know where to find me. 如果你需要帮助，你知道去哪儿找我。