When you posted your grammar question last September 14, I was incredulous at first and decided not to answer it. The question being so basic and the answer apparently so self-evident, I thought you were simply being facetious about it. While riding taxicabs these the past two weeks, however, I twice or thrice overheard conversations over the radio in which the anchor or the guest didn’t know either how to form negative sentences correctly.
This not-so-rare incidence of grammatical misuse has convinced me that there’s indeed a need to clarify the negative usage of verbs for your benefit and for others who are similarly confused or unsure about it.
We all know that the very common verb “do” can be used as either a main verb or an auxiliary verb. This is aside from its other roles in emphasizing the action denoted by a verb and in forming interrogative sentences.
As a main verb, of course, “do” means to carry out, perform, execute, or commit, as in “We will do the project as planned” and “Many politicians do violence to the Constitution’s anti-dynasty provision by brazenly fielding their own family members as candidates.”
To form negative sentences, “do,” in tandem with the main verb, works as an auxiliary verb or dummy operator, as in “The Supreme Court did not issue a temporary restraining order against the widely assailed cybercrime law.” Note that in such negative constructions, it’s always the auxiliary verb “do” that takes the tense, never the main verb.
This, then, is my answer to your question: The correct construction of that sentence of yours is “We did not participate,” not “We did not participated.” Again, let me repeat the rule in such negative sentences: It’s always the auxiliary verb “do” that takes the tense, never the main verb.
Now, in emphatic sentence constructions, we will recall that the auxiliary verb “do” is used with the bare infinitive—the infinitive minus the “to”—to emphasize the action of the verb in both the present and past tenses, as in “They do believe that some politicians have no sense of shame” and “The felons did think that they can get away with murder.” Note that in such emphatic sentence constructions, it’s also the auxiliary verb “do” that takes the tense, not the main verb.
Finally, we will recall that to form interrogative sentences, the auxiliary verb “do” works with the main verb in an inverted order to form questions, as in “Did you know that the cybercrime law is now in effect?” or “Do you realize the implications of the cybercrime law to Internet communication?” We must likewise take note that in interrogative constructions, it’s also the auxiliary verb “do” that takes the tense, not the main verb. (We must therefore perpetually banish from our mind the inane question “What did you did?” even as a joke.)
