这是一个后置定语,可以理解为定语从句的省略。比如说这是两个句子1.This is John Smith.2.John Smith is from the Overseas Engineering Company.现在的情况等于是整个第2个句子在修饰第一个句子的John Smith.首先变为定语从句就是This is John Smith who/that is from the Overseas Engineering Company.现在省略定语从句的连词who/that和从句的系动词is就变成了John Smith from the Overseas Engineering Company.