题目内容：

阅读下面短文，按照句子结构的语法性和上下文连贯的要求，在空格处填入一个适当的词或使用括号中词语的正确形式填空，并将答案填写在答题卡标号为16～25的相应位置上。

Tony and I are good friends. We tried to walk across the United States of America.We're not exactly sure 1. we were doing it. Part of it was to test ourselves; to see if we could face the challenges. When I was 2. teenager I often daydreamed that I was going to walk across the United States 3. I graduated from high school. 4. ，I didn't do that. Before I knew it I was in my thirties, married, 5. (have) a job, yet still had this idea in my mind with each 6. (pass) year. I figured I was too old and my opportunity had passed. Then, a few years ago，I met Tony, 7. was in his thirties and quit his job as a civil engineer in New York City to walk across the United States. He wasn't doing it for a cause 8. as part of an organization. He was doing it 9. （simple) because he loved to walk and discover. The idea was back and I no longer had an excuse. We planned on averaging 20 miles a day and taking some days off to rest, so we expected the walk to. take about 6 months realizing it could take 10. （long). We were in no hurry: The total distance would have been about 3，100 miles.