根据要求完成句子。

1．It took us three years to build the park．(变成同义句，每空一词)

   We           three years         the park．

2．They are going to Australia by plane next week．(变成同义句，每空一词)

   They are                      Australia next week．

3．I often go to visit my grandparents by train．(对划线部分提问)

                   you often go to visit your grandparents?

4．Sam is ten years old．Jim is twelve years old．(合为一句)

   Jim is two years                      Sam．

5．Jim has to help his mother do the housework．(改为否定句)

      Jim                 to help his mother do the housework．