你弄错了:= q.simple_fields_for :answers, q.questions.build do |a|您在构建器对象 q 而不是模型对象上调用 questions 方法.可能你想要这个:

You got it wrong here: = q.simple_fields_for :answers, q.questions.build do |a| You are calling questions method on builder object q instead of a model object. Probably You want this:

= q.simple_fields_for :answers, q.object.questions.build