完形填空，阅读下列短文, 从每小题所给的A、B、C、D 四个选项中选出最佳选项。
Mr. and Mrs. Green were very worried about their son, Leo. He seemed to be dumb (哑的) 1 he was normal in every other way. Mr. and Mrs. Green tried everything to get him to 2 , but with no success.
When Leo was six years old, the best doctors in the town 3 him carefully, but could find nothing wrong. And he seemed to be smart. It was just that he 4 spoke.
"There might be something wrong with his 5 , and he doesn't know he's able to speak," one doctor said.
"But he can read and write," said Mr. Green. "We've written him notes, telling him that he can speak."
"It's certainly very 6 ," another doctor said. "Perhaps he'll be able to speak some day."
7 passed. Leo went to university. But he did not speak a 8 word.
Then one day, Leo was having a meal with his parents. Without any warning, he looked up from his 9 and said, "Pass me the salt, please."
Mr. and Mrs. Green were excited. "You spoke! You spoke!" they cried, "Why have you 10 so long to speak?"
"I didn't have anything to say," he said. "Until now everything was perfect. But you forgot to put salt in these potatoes."
( )1. A. because B. when C. though D. before
( )2. A. speak B. walk C. play D. laugh
( )3. A. taught B. found C. examined D. asked
( )4. A. never B. often C. usually D. always
( )5. A. back B. hair C. face D. mind
( )6. A. unfair B. strange C. noisy D. quiet
( )7. A. Hours B. Weeks C. Months D. Years
( )8. A. good B. right C. single D. new
( )9. A. chair B. meal C. hands D. books
( )10. A. slept B. walked C. served D. waited