The morphological marking that distinguishes conditionals that are called “counterfactual” from those that are not, can also be found in other modal constructions, such as in the expression of wishes and oughts. We propose to call it “X-marking”. In this article, we lay out desiderata for a successful theory of X-marking and make some initial informal observations. Much remains to be done.

中文翻译：

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X 标记理论序言

区分被称为“反事实”的条件句和非“反事实”条件句的形态学标记也可以在其他模态结构中找到，例如在愿望和应该的表达中。我们建议将其称为“X 标记”。在本文中，我们列出了成功的 X 标记理论的必要条件，并进行了一些初步的非正式观察。还有很多工作要做。