Those pesky adverbs

As I will be arguing in a following section (see 2.5), temporal adverbials function as parallel structures to tense markers. They make use of all the parameters of tense, and introduce certain additional parameters as well, and further, they are able to provide greater detail in the case of all these parameters.. However, it is necessary to describe the system of tense independently of these adverbials because the latter are only optional elements that may be used to modify tense, if necessary; they do not form an essential part of the tense system.—The Prominence of Tense, Aspect and Mood, page 30

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A very interesting book. Lots of stuff is falling into place as I read this. Maybe someday I'll even understand it : )
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