It was Clark' s first visit to London Underground Railway. Against【C1】______ advice of his friends, he decided to go there after 5 o' clock in the afternoon. This is a bad time to【C2】______ in London, because numerous people go home from work【C3】______ this hour. He had to join a long【C4】______ of people who were waiting for tickets. When his turn came, he had some difficulty in making himself【C5】______by the man selling tickets. However, he got the right ticket【C6】______ the end and, by asking people the【C7】______ , he also found the right platform. It was packed tight【C8】______ people. He did not【C9】______ to get on the first train, but he was【C10】______to move nearer to the edge of the platform so as to be in a better【C11】______ to get on the next one. When this train came in, Clark was【C12】______ forward on to the train by the【C13】______ of people from behind. The doors closed and the train【C14】______ off. He was unable to see the names of the stations where the train stopped, but he knew that the station he wanted was the sixth【C15】______ along the line. When the train got to the sixth station, Clark got off, feeling good that his【C16】______ had been so easy. But he suddenly【C17】______ that he had come to a station he had never heard of. He explained his difficulty to a man who was standing on the platform. With a【C18】______ on his face, the man【C19】______ Clark that he had caught a train going in the opposite【C20】______ .