阅读理解(2014北京)
　　Billy’s favorite color is orange．But he can’t see what orange looks like．Billy is blind．
　　A month after he was born，his mother noticed that his eyes weren’t quite as big as a normal baby’s．“Billy would never be able to see，”the doctor told his mother．After that Billy’s mother began talking to him，describing things she saw．She told him what she was cooking，or what she saw outside the window．She described everything to him．
　　Billy does not only depend on his mother’s descriptions to learn about the world around him．He sees with his cars and his hands，too．He has perfect hearing．When people make phone calls，he can tell the numbers they dial(拨)．
　　“He is very confident and his disability doesn’t stop him from being an important part of the class，”his teacher said．“The students love him，and he is just one of them．”
　　Billy loves computer science．He began teaching himself computer programming when he was just seven years old．His dream school would be Stanford University．He gets top grades in his classes，making that a real possibility．
　　“You can’t let excuses get in the way of your dreams，and if you do that，you can’t move forward and reach your goals，”said Billy．
From the passage，we know that________．

A．Billy can’t hear

B．Billy can’t see

C．Billy can’t walk

D．Billy can’t talk

How did Billy’s mother help him？

A．By teaching him how to draw．

B．By asking teachers for advice．

C．By describing everything to him．

D．By sending him to his dream school．

When did Billy begin teaching himself computer programming？

A．When he was 7 years old．

B．When he was in Grade 5．

C．When he was in high school．

D．When he was at university．