impairment(视力损害) made a small but encouraging step last week when he bravely managed to get over his school's curb(路缘石) by himself for the first time.

　　 Gavin Robert Stevens was diagnosed (诊断) with Leber's congenital amaurosis (LCA), when he was just 4 months old. The eye disorder causes serious vision impairment from a young age.

　　 When doctors told Gavin's parents, Troy and Jennifer Stevens, that their little boy was blind, they felt their lives were "turned upside down"．

　　 That fight continued last week, when his mother recorded 4­year­old Gavin using his white stick to step off a curb at his school all by himself. "These steps, while small, are important for Gavin to develop self­reliance and self­confidence，" Jennifer Stevens said.

　　 "We've been working on steps. For someone who is blind, such things need to be taught，" Stevens said. "On this particular day I went to take his hand, and he didn't want me to hold his hand."

　　 As Gavin got over the curb, you could hear the stress and the hesitation(犹豫) in his voice, his mother said. But slowly, Gavin stepped down onto the pavement.

　　 "He gets very happy when he does things independently for the first time，" Stevens said. "It's such a joy to him."

　　 Stevens said she records these achievements both for her family and for the other families nationwide whose children also have LCA. Each video provides a little hope, she said.

　　 The family has been raising money for research that may one day lead to effective gene replacement therapy(基因替代疗法). In the meantime, Gavin keeps working on a lot of little things. Gavin loves playing the piano, singing in the car and studying at the music academy he attends in Southern California. He's also learning to read Braille, and he recently learned how to identify the letter "G"．

　　【文章大意】　本文是记叙文。患有先天性利伯氏黑蒙的4岁男孩Gavin利用手杖迈出了人生的第一步。

　　1. When Gavin's parents learned of his disease, they felt ________.

　　A．it was not a serious disease

B．they had no hope of saving Gavin