否定句：The children hadn't a picnic in the park.
一般疑问句：Did the children have a picnic in the park?
对划线部分提问:没有线啊!有以下几种可能：
1).the children 划线：Who had a picnic in the park?
2).had a picnic 划线：What did the children do in the park?
3).in the park 划线：Where did the children have a picnic?