PHP as a whole consists of 3 modules (Core PHP, Zend Engine and Extension Layer)

PHP总共有三个模块：内核、Zend引擎、以及扩展层；

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Here, software such as the Zend Engine takes the time to optimize the opcodes produced during compilation, literally reducing the amount of work that the code performs.

此处，Zend Engine之类的软件会优化编译过程中产生的操作码，这理论上会减少代码执行的工作总量。

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