what are the M Triplets helping verbs?

There's no grammatical concept called "M Triplets" in English. It's possible you're thinking of a different term or are referring to a specific context where this phrase is used.

Could you please provide more information or clarify what you mean by "M Triplets helping verbs"?

Perhaps you're thinking of:

* Modal verbs: These are helping verbs like *can, could, may, might, must, shall, should, will, would*. They are used with a main verb to express different moods or tenses.

* The three forms of "to be" as helping verbs: *am, is, are, was, were, being, been*. They are used to form progressive tenses and passive voice.

Let me know if any of these options are what you had in mind, or if you have another term or context in mind!