You mustn't play football in the fields,____ ____?(改为反意疑问句)

问题描述:

You mustn't play football in the fields,____ ____?(改为反意疑问句)

mustn't you?
must表示必须时,反意部分应该用mustn't
must表示需要时,反意部分用needn't
根据句子意思,这里要用mustn't.