Определить, являются ли выделенные знаками "_ _" формы глаголов to be, to have, to do самостоятельными или вспомогательными. Определить видовременную форму (т.е. время и залог) сказуемых. Помогите, пожалуйста!

1. In ancient times these lands were crossed by the trade routes of cities belonging to the medieval Hanseatic League, and later on, during the reign of Peter I, artificial waterway systems were constructed to connect the regions of Central Russia and the Volga area with Western European countries.

2. The Leningrad region _enjoys_ a very favorable geographical location.

3. Its advantageous geopolitical position in the system of world economic relation and the new role it _started_ to play in linking the Russia with the rest of the world after the disintegration of the former Soviet Union _have played_ a decisive part in its development.