根据所给要求，改写下列句子。每空格限填一词。
1. The new flat cost Mr. Black a lot of money. (改为否定句)
The new flat ______ cost Mr. Black ______ money.
2. The red bike belongs to my mother. (对划线部分提问)
______ ______ belongs to your mother?
3. Whiz-kid Wendy's never late for work.（改为反意疑问句）
Whiz-kid Wendy's never late for work, _____ _____?
4. The boy is so strong that he can carry the heavy safe easily. (改为简单句)
The boy is strong ______ ______ carry the heavy safe easily.
5. By the time he was six, he had started learning Japanese. (保持句子原意)
He ______ learning Japanese ______ he was six.
6. James Nai. Smith, a Canadian doctor invented basketball. (改为被动语态)
Basketball ______ ______ by James Nai. Smith, a Canadian doctor.
