Use the Past Perfect Continuous and the Past Simple to form complete sentences. 4. Before Russian chemist Dimitri Mendeleev become famous around the world/work as a university professor/some years

Перевод задания: Используйте Past Perfect Continuous и Past Simple, чтобы составить полные предложения.

4. Before the Russian chemist Dimitri Mendeleev became famous around the world, he had been working as a university professor for some years.
   До того как русский химик Дмитрий Менделеев стал известен во всём мире, он несколько лет работал профессором университета.