按括号内的要求转换下列句式，每空一词。
1. Midori was born in 1971. (对划线部分提问)
______ ______ Midori born?
2. He hiccupped for six years. (对划线部分提问)
______ ______ did he hiccup?
3. He began to play for his national team when he was 15. (变为同义句)
He began to play for his national team at the ______ ______ 15.
4. Charles Smith won first prize in his group. (对划线部分提问)
______ ______ first prize in his group?
5. He could hum songs when he was a small boy. (改为否定句)
He ______ ______ songs when he was a small boy.