Question

 ارتقاء رتبه شامل چهار سطح پایه، ارشد، خبره و عالی می باشدکه دوره زمانی برای کسب آنها متناسب با سطح مشاغل از6 تا 8 سال متفاوت است

Answer 1

Promotion includes 4 basic, senior, expert, and excellent levels that the period for acquiring them is proportionate to occupations' level and varies between 6 and 8 years.

Comments

Nice+

I would write "..... level VARYING...." 

 

Promotion includes 4 basic, senior, expert, and excellent levels that the period  required for acquiring them proportional to occupations' level varies between 6 and 8 years.

---

Thanks. Both are correct.