English term
It's time sb did/"do(es?)?" sth
Notwithstanding, in specialized discussion forums you get people maintaining the following:
1) The SUBJUNCTIVE of the verb is also standard (?!), despite hardly ever used (!!). [Note: all of them always give as examples "It's (about/high) time YOU DO sth"; not a single mention if "do" may or must be inflected for singular third persons.].
2) The PRESENT TENSE of the verb in coloquial American speech is common usage, being naturally avoided in educated English.
...Other, say, explanations, are not really worthy of mention, given their absurdity.
But even an OED, under the entry "want", brings the line " “It's time you do your homework.” “I don't want to!” ", but that's all. http://oaadonline.oxfordlearnersdictionaries.com/dictionary/...
Finally throughout the Internet, where examples abound:
[NY TIMES] "(...) decides it's time she does something to improve her life. http://movies.nytimes.com/movie/239438/Der-Schone-Tag/overvi...
[FLORIDA TIMES UNION] "(...)It’s time he does something for ordinary, honest Florida families,” Karp said."
http://jacksonville.com/news/metro/2013-09-11/story/gov-rick...
Question:
Being a colloquialism -- American? -- it is then a case where the presente tense functions as a subjunctive, and at that being inflected in the 3rd persons sing.?
[ISN'T THERE A SINGLE GRAMMAR OR DICTIONARY REGISTERED THIS PATTERN AS COLLQUIALISM, IF SIMPLY TO SAY IT IS TO BE AVOIDED?!]
| 4 +11 | did / does |
Tony M
|
| 5 | did |
Mike Birch
|
Non-PRO (1): Tony M
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Responses
did / does
2) In most verbs, the subjunctive has the same form as the imperfect indicative — but not all! Cf. "Be it e'er so humble, there's no place like home"
3) In common, everyday usage, in both American and British English, there is a tendency to use the indicative all the time — to the extent that it can now no longer be considered an 'error'; the use of the subjunctive is perhaps to be encouraged in more formal writing, but in everyday conversation can sound dated and/or pretentious.
4) Irrespective of the tense used, the subjunctive inflects (notably in the 3rd person) just as for any other verb.
"If I were you, I'd buy a new car" — here, the subjunctive is commonly used, and still even today, I feel that "If I was you..." suggests an uneducated speaker; indeed, writers often use it as a device to indicate the educational background and/or age of a character.
"Were he to come, I'd give him a piece of my mind" — here, in this particular construction, I think almost everyone would agree that 'was' sounds quite wrong. The subjunctive here re-inforces the expectation that he will not come. But cf. "If she comes Tuesday like she usually does, I'll give it to her"
In your particular example, one might draw a parallel: "It's high time he did something about his torn shirt" (but we don't think he's going to...) but cf. "It's high time for her to do her homework" (and indeed she is going to...)
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Note added at 11 hrs (2013-10-09 15:58:16 GMT)
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In answer to your parting question: the use of 'does' instead of 'did' in your example is not "the present tense being used as the subjunctive" — it is just a case of the speaker's / writer's ignoring the subjunctive altogether.
In the specific case of the verb 'do', it inflects normally whether in the subjunctive or indicative. 'to be' is irregular in this respect: if I/you/she were, if I/you/she be. Cf. the irregularity of 'to be' in very many Western languages.
Native in: English 
, French
Works in: French to English, English to French, English, and 3 more.
did
As asker states, the grammatically correct formation is past tense with present/future meaning.
As an example insert a proper noun:
*"It's time Mike were in bed" has a conceivable interpretation as subjunctive (uncertainty), but "Mike should be in bed by now" is much more obvious/natural if that meaning is required.
*"It's time Mike go to bed" is clearly wrong.
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Note added at 2 days7 hrs (2013-10-11 11:48:52 GMT)
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Should have read *"It's time Mike goes to bed" for second counter-example.
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