Translation of ergänzen

A bystander who watched the entire scene all the time decided to help me. He was an older man, around seventy, but nonetheless he went to the oldest of these kids and slapped him. The boy was sixteen.
There were mountains. The heat of the day stand for the atmosphere between the man and the woman. They are waiting for the train from Barcelona to Madrid at a station between the two cities.
On the way we visited many small hill tribe villages. The walk was through green, wet rice fields. We really enjoyed it. Our guide explained us about the region and taught us some Vietnamese.