A、A fan who likes her song. B、A little boy died of cancer. C、A rock star named Ronan. D、A cancer research centre. B文章在开头部分提到，到目前

(20 -1)By now you may have heard Taylor Swift’s heartbreaking song " Ronan" , about the too-short life of a little boy. Ms. Swift gave it an emotional performance on the Stand Up to Cancer television program on Sept. 7, and it has been topping the charts ever since.
     (20 - 2)The real boy behind the song is Ronan Thompson, a naughty 3-year-old boy from Phoenix with coppery blond hair and big blue eyes. In 2010, a few months after his third birthday, Ronan was given a diagnosis of cancer, an often deadly childhood cancer. He died on May 9, 2011, three days before he was to turn 4. It’s the most common cancer in infants and accounts for about 15 percent of all childhood cancer deaths.
     (21)Ms. Swift learned about Ronan from a blog that his mother, Maya Thompson, began shortly after the diagnosis to keep family and friends informed. Ms. Thompson called the blog Rockstar Ronan, but she did not tell directly about his illness, and her heartbreak was painfully evident in every update. Ronan spent his last days in a hospital in Phoenix with his parents and brothers. After he died, his mother continued to write tearful posts on her blog, which had turned into an open letter to her son.
     (22)Cancer is the second leading cause of death of children under 15—after accidents—yet childhood cancer receives only 3 to 4 percent of national cancer research funds. Although childhood cancer is considered rare, an estimated 12,060 new cases are expected this year among children 14 and younger. The survival rate for childhood cancer is about 80 percent.
20. What is Taylor Swift’s song " Ronan" about?
21. How did Taylor Swift learn about Ronan?
22. What is the first leading cause of children death under 15?