Declaring one with extern or static is erroneous .

把一个内嵌函数声明成extern或是static是错误的。

In certain circumstances , the extern declaration can be omitted .

某些情况下可以省略extern声明。

In enter decor stage , extern thermal insul can do with intern decor simultaneously , shorten the construct period .

进入装修阶段时，做外保温可与做内装修同时进行，缩短施工工期。