句式密度 Syntactic Pattern Density
Syntactic complexity is also informed by the density of particular syntactic patterns, word types, and phrase types. Coh-Metrix provides information on the incidence of noun phrases (DRNP, verb phrases (DRVP), adverbial phrases (DRAP), and prepositions (DRPP). The relative density of each of these can be expected to affect processing difficulty of text, particularly with respect to other features in a text. For example, if a text has a higher noun and verb phrase incidence, it is more likely to be informationally dense with complex syntax.
句法复杂性还可通过特定句法模式、词类型和短语类型的密度来了解。Coh-Metrix 提供了有关名词短语（DRNP）、动词短语（DRVP）、副词短语（DRAP）和介词（DRPP）出现率的信息。这些词组的相对密度预计会影响文本的处理难度，特别是与文本中的其他特征相比。例如，如果一篇文章的名词和动词短语出现率较高，那么它就更有可能是信息密集、句法复杂的文章。