求指点一个true的用法

题目

求指点一个true的用法
There remains today a stubborn,widespread fantasy that libraries will buy enough copies of a book to pay for the cost of producing it.【True】,once upon a time,a university press could expect to sell about 1,500 copies of a typical monograph,with 800 to 1,000 of those sales to academic libraries.
请问此外的true是不是it is true that的省略形式?

答案

我觉得true在这里是副词,相当于exactly,作状语.
比较一下这两个不同的用法：
1.Humble and true,he never lies.
这句里的true是形容词,前面省略了being：
Being humble and true,he never lies.
2.True,he always goes home after work.
这句不能改成being true,意思完全不一样了.虽然改成it is true that意思会一样,但是语法结构不一样,所以不是it is true that的省略形式.