Предлог или наречие. Once Mark Twain was sitting......a dinner party.........a well-known pianist. He said......him:

Once Mark Twain was sitting at a dinner party with a well-known pianist. He said to him: It will interest you as a pianist that my life was once saved by a piano when I was a boy. We had a ter­rible flood in my home town. The water even reached the upper storey where I was with my father. Without hesitation my father sat on a big chest of drawers, and floating down the river reached safely the bank.\" \"Well, and you?\" asked the pianist. \"I accompanied him on the piano.\"A Londoner who was going to the West of England for a holiday, arrived by train at a town, and found that it was pouring.  He called a porter to carry his bags to a taxi on the way out of the station, partly to make conversation and partly to get a local opinion on prospects of weather for his holiday, he asked the porter: \"How long has it been raining like this?\" \"I don\'t know. Sir, I\'ve only been here for fifteen years,\" was the reply.