他们研究这门工作已有多年了的翻译：They study the doors have been working for many years 什么意思？中文翻译英文，英文翻译中文，怎么说？

青云英语翻译

They study the work of many years of door

They study the doors have been working for many years

They study this work to have many years

They have been working as a study of this door has over the years

They study the doors have been working for many years