Translation of lethargic in German

I was wondering if you can tell me if few words how to study here because I don't know that's why I'm not on line most of the time,thanks. Can you help me explaining me how to do the lessons, I still don't understand it
After ten minutes and after drinking a bottle of water we returned to our place. It was already three in the morning. We were unhappy to miss a great party, but our physical conditions were bad.
In the late afternoon we took a taxi back to Cusco, which we shared with a nice Spanish couple. My wife who was mainly concerned with our sleeping conditions took the address of their hotel.