[解析]
(1)A.细节理解题.由第一段It was not until in my late thirties that I made this important discovery可知,直到年近四十,作者才有了一个重要发现,故选A
(2)B.理解推断题.由第二段If an idea for improving the window display of a neighborhood store flashes to me,I step in and make the suggestion to the storekeeper,可知作者自己做出了这个建议,故选B
(3)C.理解推断题.由最后一段More than a year later I needed a post office box for a new business I was starting.I was told at the window that there were no boxes left,and that my name would have to go on a long waiting list可知,有许多人在作者之前已经申请过了邮箱,故选C