Задайте разделительные вопросы: 1.russian researchers have been doing much for the development of metallurgy as a science 2.the main building of our institute isn't lenin street 3.second-year student will study physical metallurgy next year 4.olga takes many subjects at the institute 5.students understood a new rule

1.Russian researchers have been doing much for the development of metallurgy as a science, haven`t they?
2.The main building of our Institute isn't in Lenin Street, is it?
3.A second-year student will study physical metallurgy next year, won`t he?
4.Olga takes many subjects at the Institute, doesn`t she?
5.Students understood a new rule, didn`t they?