1.(否)My mother was't at home yesterday.
(一般) Was your mother at home yesterday?Yes,she was.
(提问) When was your mother at home?
2.(否定句)The boy didn't fly a kite.
(一般) Did the boy fly a kite.
(否定回答) No,he didn't.
(提问)Why did the boy fly a kite?
3.(否定)The students didn't go to the park by .
(一般) Did the students go to the park by.
(提问) How did the students go to the park for the holiday?