翻译成英文，别找翻译器

Architectural decoration project specialized contracting grade two.

Building decoration engineering contractor - 2

一般多少级就直接用数字表示就可以了。
比如说大学英语四级是CET-4
全国公共英语等级考试四级是PETS4
以此类推。

我想你的这个级数也是数字表示就可以了。

the second grade for Building Decoration Engineering

建筑 Building
装饰 Decorate
装修 Decorate
工程 Project
专业 Special field
承包 Be contracted by
贰级 Grade-two
建筑装饰装修工程专业承包贰级;
Architectural decoration fitting up project special field
contracts grade-two