XML is not tied to a particular programminglanguage or operating system, thus it can be used as a protocol for information exchange between heterogeneous systems.
XML并不局限于某种特定的编程语言或操作系统，因而，它可以被用作异构系统间的信息交换协议。
2
The purpose of a programminglanguage is to help build good systems, where "good" can be defined in many ways.
一种编程语言的目的是帮助程序员建立好的系统，而“好”的定义多种多样。
3
A number of issues creep up when it comes to taking the programming languages everyone used for back-end systems and leveraging them to generate markup language suitable for a client.