Auxiliary verbs

Question

I have seen many times that two same auxiliary verb used in one sentence together(e.g - have have). I don't understand this type of sentences. Please help me.

Answer 1

There are four basic types of auxiliary: modal auxliaries—auxliaries used to express a modality, perfective auxiliaries—forms of HAVE indicating a perfect construction, progressive auxiliaries—forms of BE^† used to mark a progressive aspect, and passive auxiliaries—forms of BE used to mark a passive voice.

You can only have one auxliary of a particular type. You cannot have two or more modal auxiliaries, two or more perfective auxiliaries, and so forth. So this combo is not possible

*You must can go away (ungrammatical because two modal auxiliaries occur consecutively)

But you can say

You must have made a mistake (OK, it's a combination of a modal and a perfective auxiliary. For more, see our canonical post)

The combination of two forms of have you encountered is just a construction of perfect. It's combination of the perfective auxliary HAVE and a past participle have. This is usually referred to as a present perfect.

I have had a headache.

You may also come accross the past perfect with a have as the main verb.

I had had a headache.

---

^† _{Forms of BE include am, is, are, were, be etc.}

_{Any asterisk (*) herein is used to mark an ungrammatical utterance, not to indicate a footnote.}

Answer 2

Do you have a specific example? I can't think of a meaning for "have have". However, I can definitely think of examples where "have had" or "had had" could be used.

He had had too many drinks.

"At the point in the past currently being discussed (first "had"), he had drunk too much."

I have had this feeling all day.

"Starting with the beginning of the day (since I woke up), I have been feeling strangely."

Note that in each case, the second "had" is a participle of the verb "have". It's not acting here as an auxiliary verb at all, but rather as the normal verb "to have", meaning to own, to possess, to experience, etc. in any kind of conversational case (or writing that attempts to be faithful to the spoken forms), these would most likely be contracted down to:

He'd had too many drinks.

I've had this feeling all day.

Finally, just for fun:

He hadn't known [that] he had been had.

Here the last "had" is a colloquialism meaning "fooled."