来自 http://www.w3.org/TR/xpath/#section-简介

计算表达式以产生一个 对象，具有以下之一 四种基本类型:

An expression is evaluated to yield an object, which has one of the following four basic types:

• 节点集(无重复的无序节点集合)
• 布尔值(对或错)
• 数字(浮点数)
• 字符串(UCS字符序列)

• node-set (an unordered collection of nodes without duplicates)
• boolean (true or false)
• number (a floating-point number)
• string (a sequence of UCS characters)

因此，XPath 1.0中没有xs:string的序列

So, no sequence of xs:string in XPath 1.0

在XPath 2.0中，当然有一个序列数据类型...

In XPath 2.0 there is a sequence data type, of course...