A beautiful girl about my age, she bought the ticket for me when hearing that I had lost my wallet.

▲ 本句中的A beautiful girl about my age，说它是she 的同位语，未免过于草率和简单。正如网友所言，它不符合同位语的基本概念。那么，A beautiful girl about my age 在语义和语法上，它跟后面的句子是何种关系呢？

我认为，A beautiful girl about my age 是一个名词性短语，放在句首，是对后面句子所要表达的句意，具有提示性作用。所谓提示性作用，就是为了后面的句子要表达某种含义提供更多的信息。它相当于一个存在句：There was a beautiful girl about my age. She bought the ticket for me when hearing that I had lost my wallet. 暗示着这个跟我年龄相当的女孩不但漂亮，还助人为乐，相比之下，自己深感不如。

在语法作用上，A beautiful girl about my age 作提示性状语，修饰后面的全句或谓语动词。

▲ 在2014年广东省高考英语试题中，就有类似的句子：

A scientist with many years’ experience, he started this type of research in the early 1990s when he heard about hundreds of athletic shoes washing up on the shores of the northwest coast of the United States.

本句中，A scientist with many years’ experience 也是为后面的句子要表达某种含义提供了更多的信息。也相当于一个存在句：There was a scientist with many years’ experience. He started this type of research... 该名词短语说明这位科学家经验丰富，读者自然觉得他的研究是可信的，或者说为之后研究的成功埋下了伏笔。