were they afraid of snakes in the past?
Yes, they were.
No, they were not.
did the students play football in the playground just now?
Yes, the students did.
No, the students didn't.
第四和第五题无法做一般疑问句, 但可作特殊疑问句.
what did you learn at school yesterday?
where did Jack and his friends go camping last week?