Q: If I ask a question like “Have you got a screwdriver?” and someone answers, “I do,” it sets my teeth on edge. I extrapolate that to mean “I do got.” Is that answer incorrect, or is it just me?
A: The use of “I do” in reply to “have you got” is a normal and correct construction in English. There is no “rule” against this common usage.
What’s thrown you off is the idiomatic verb construction “have got.” Both the Oxford English Dictionary and The Cambridge Grammar of the English Language say “have got” here means “have” (in the sense of own or possess). Oxford calls it a “specialized” usage while the Cambridge Grammar calls it an informal idiom.
So in the type of question you mention, “have got” and “have” are interchangeable. And whether it’s worded “Have you got a screwdriver?” or “Do you have a screwdriver?” the question has several grammatically correct replies, including (1) “Yes I have” and (2) “Yes I do.”
Both of those are elliptical replies, in which the verb is stranded at the end. They might be expanded as “Yes I have [or have got] a screwdriver” and “Yes I do have a screwdriver.”
So as you can see, the “do” in reply #2 is elliptical for “do have,” not “do got.” As the Cambridge Grammar explains, the “got” in the idiomatic “have got” cannot be stranded at the end of a sentence. This means that in an elliptical construction with a verb at the end, an auxiliary like “have” or “do” is used.
Keep in mind that “have you got” is an idiom to begin with, so it’s not unexpected that the common reply—“Yes I do,” or “No I don’t”—should be idiomatic too.
Fowler’s Modern English Usage (4th ed.) says that in answer to a “have you got” question, the “do” reply is a familiar feature of both British and American English. Fowler’s, edited by Jeremy Butterfield, offers this analysis:
“Question: Have you got a spare room? Answer: Yes, we do. This apparently illogical use of do, replacing have as the auxiliary verb, arises because the question implicitly being answered is ‘Do you have a spare room?’ It is a common pattern in AmE and causes less surprise to British visitors than formerly, since it has also become a feature of BrE.”
In ordinary usage, rather than in the idiom, “have got” is the present perfect tense of the verb “get,” with “have” as the auxiliary (as in “I have got infected”). But in the idiom we’re discussing, the OED says, “have got” functions as the present-tense equivalent of “have.”
And “have” in the idiomatic “have got” is the main verb (not an auxiliary). So both grammatically and semantically, “I have got” = “I have.” In fact, the question “Have you got a screwdriver?” could be rephrased more formally as “Have you a screwdriver?”
(We might add that many speakers find a sentence like “Have you a screwdriver?” to be excessively formal. Americans in particular seem to prefer questions phrased with “do” when there’s a direct object: “Do you have a screwdriver?”)
You might wonder why English speakers started using the idiomatic “have got” in the first place. After all, the simple “have” performed that function for hundreds of years, and still does.
As we said in a 2014 post, there are two theories about the likely origins of this usage, which dates back to Elizabethan times.
One is that the verb “have” began losing its sense of possession because of its increasing use as an auxiliary. Thus “got” was added as an informal prop.
The other theory is that “got” was originally inserted because of the tendency to use contracted forms of the verb “have.” So if a sentence like “I’ve a cat” felt unnatural or abrupt, one could use “I’ve got a cat” instead.
We should mention another familiar idiomatic use of “have got”—the one that means “must.” Here too, the “got” is not essential to the meaning. “I have got to leave” = “I have to leave” = “I must leave.”
And again, a “do” reply to this variety of “have got” question is perfectly acceptable: “Have you got to leave?” … “I do.”
The “have got” that indicates obligation or necessity is followed by a “to” infinitive, like “to leave.” (The other “have got” idiom, the one indicating possession, is followed by a direct object, like “a screwdriver.”) We wrote about this usage in 2010.