Формы глаголов: picked, closed, found

Pick - picked - picked - picking close - closed - closed - closing find - found - found - finding (находить) есть ещё такой  глагол: found - founded - founded - founding (основывать, создавать)

Это past simple если время глаголов

1. economists are interested in the problems of factors that affect prices of goods and services and necessary recourses to produce them, as well as  sellers' and buyers' behaviour in the market and  the relationship between "price system" and "market mechanism"2. three main approaches to economics are  microeconomics, macroeconomics, and development economics.3. specialized areas of economics are  money economics, international economics, labour economics, industrial economics, agricultural economics, growth economics, mathematical economics, etc.4. economists use economic models  to understand economic problems and make correct predictions5.  it is not possible to include all the details in a model because real life is complex and a model is an abstraction from real life.  6. a model usually include essential elements and relationships of a particular economic situation7. an economists choose the model that predicts the results of a particular phenomenon more accurately8. it is necessary to collect and study actual data in order to know how accurate a model is