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.