Вставьте в предложения подходящие по смыслу слова из предложенных групп однокоренных слов: differ, different, difference; to vary, various, variety; efficient, efficiently, efficiency.
1. The enterprise is working … .
2. There is a … of reasons for high unemployment in this region.
3. Prices of the same agricultural products … from region to region.
4. There is not any … between these two methods, only the names … .
5. These two economists are interested in … fields of economics.
6. They have raised … of their work by means of new machinery.