The following revision is taken from the Conclusion of an essay by a Chinese-speaking student of Law:

Original	Revisions
It is still not clear whether decisions that departed from the Salomon doctrine were principled and achieved certainty and justice	It is still not clear whether the decisions that departed from the Salomon doctrine were principled and achieved certainty and justice
	It is still not clear whether decisions that depart from the Salomon doctrine can be principled and achieve certainty and justice.

It is not clear from the original drafting whether the Conclusion relates only to the decisons discussed in the essay (the 'Specific' interpretation) or relates to decisions of the type that are discussed in the essay (the "Non-specific" or "General" interpretation).

1. For the Specific interpretation, the Definite article marks the 'decisions' as specific: The Past Tense on the verbs ('departed' ... 'were principled' ... 'achieved') relates to the specific times at which those decisions were made.

2. For the Non-specific interpretation the Zero article is needed with 'decisions' (ie any decisions ...)., and the tense of the of the verb is present since there is no specific time for those decisions. Since no specific decisions are referred to, the question is not whether they are principled and do achieve certainty and justice, but whether they have the potential to do so: thus the use of the modal 'can' ('can be principled and [can] achieve ...').

Given the choice, the student chose the Non-specific revision.

This sentence illustrates how choices at different points in the grammatical system interact (here parallel choices of specificity in the Noun Phrase and the Verb Phrase). Such interactions are likely to be missed in traditional pedagogic presentations of grammar in which choices of Definite or Zero Article, of Past or Present Tense, or of Modal verb, are dealt with separately and without reference to underlying patterns of meaning.