按要求句型转换：Mary was riding a bike at that time否定句

网友回答

否定句: Mary wasn't riding a bike at that time.
一般疑问句 Was Mary riding a bike at that time?
肯定回答Yes, she was.
否定回答 No, she wasn't .
特殊疑问句: What was Mary doing at that time ?
======以下答案可供参考======
供参考答案1:
否定句：Mary wasn't riding a bike at that time .
一般疑问句：Was Mary riding a bike at that time ?
肯定回答：Yes,she was .
否定回答：No,she wasn't .
特殊疑问句：What was Mary doing at that time ?