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

问题描述:

按要求句型转换:Mary was riding a bike at that time
否定句____________
一般疑问句
两回答
特殊疑问句

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 ?