When to use verbs with an s or without

Your teacher is correct. This is the subjunctive in English. It may be more clear to say "It is urgent THAT Molly prepare a revised document...."

A very commonly-used verb in subjunctive form is 'to be':

If I were you, I would prepare that revised document before the boss comes in this morning.

That was awfully cavalier of you, Emily!

That's because it's in the subjunctive. The subjunctive is often used to express hierarchical differences in the English language (e.g. Queen always speaks in the subjunctive) or simply a higher sense of authority. It implies that the demands are absolute and incontestable.

Another use of the subjunctive is during hypothetical situations that you completely do not anticipate.

However, the subjunctive is rarely used in English, so don't worry about it.

There are 4 forms that are called the subjunctive.

1. the frozen subjunctive, which exists in set phrases like "God save the queen" and "be that as it may".

2. the uninflected used in dependent clauses (called the "mandative subjunctive"):
I insist that you be quiet.
I demand that this cease.

3. the inverted "had" and "were", as in Had I known this yesterday, I would have done something. Were I going to Paris, I would learn French.

4. the "were" form used with first and third person singular in counterfactual clauses:
If I were in Paris, I would learn French.
I wish she werenÂ’'t going away.
However, "was" is also acceptable here. Writers have been using "was" and "were" interchangeably in counterfactual clauses for about 300 years.

Emily, what about the subjunctive makes it "necessary" in French and "silly" in English? Contrary-to-fact statements (those which - in general - express doubt) exist in both languages. German even has its subjunctive 1 form that employs a specialized form of verb when quoting someone indirectly. In a word, the subjunctive mood adds a certain elegant specificity to both written and spoken language. Without it, our language (and others) would be far less refined.

Whether you think the subjunctive makes English sound more refined or not, many languages don't have it and manage just fine.

Indeed, it is my opinion that the subjunctive is an aspect of the English language that makes it richer and more diverse than those lacking this grammatical mood. Certainly each language contains areas which give it more depth, and English lacks in many areas compared to others (such as lacking a variety of different "you" command forms or not having gender-specific 3rd person plural pronouns)...
I recently read an article in New Yorker about a remote Amazonian language called Piraha that lacks both reclusion (also known as embedding), as well as the concept of numbers above 2 or 3 AND the idea of color names; these features were considered by the Chomsky school of thinking to be universally inherent in languages. The argument by the linguist who spent over 25 years living within the tribe and acquiring the complex sing-song of the language is that what it lacks in those basic elements, it greatly makes up for in its scope of forest-specific vocabulary and descriptive terms.

Everett's theory on Pirahã might implications for linguistics, if it is true. But it's not yet clear how true it is. Further research is needed.

otoh it might be no big deal:

http://itre.cis.upenn.edu/~myl/languagelog/archives/004592.html

John, thank you for the link. Indeed the subject requires extensive further investigation. I for one do not mind sitting on the sidelines watching the tug-of-war match unfurl. I have to think that Dan Everett has no ulterior motive for putting forth his assertions. More convincingly, he is the foremost expert on the Piraha language and culture.

i meant infinitive

We can certainly overcomplicate English by thinking about it too much sometimes.

To me, the short answer is that this particular use of the subjunctive verb form (John's "Number 2 form") appears destined to become increasingly optional. Indeed, it seems sometimes in British English that there's almost a deliberate campaign to eradicate the form.

Emily is wrong to say the subjunctive is "silly" but actually quite right to say it is not as necessary in English as it is in French.

And why is it necessary in French?

Because it is. Language is like that.

Long live The Subjunctive!

The subjunctive is unnecessary only to those who wish to remain limited in their ability to express themselves with the full range of nuance that English allows. However, why one would wish to remain less than fluent in one's native tongue strikes me as peculiar.

"However, why one would wish to remain less than fluent in one's native tongue strikes me as peculiar."

Exactly how does not using the subjunctive forms (such as they are) make one "less than fluent in one's native tongue"?

The idea that one could become less than fluent in one's native tongue strikes me as peculiar.

Does nobody bother to use a dictionary anymore?

fluent as defined by Merriam-Webster:

Main Entry:
flu·ent Listen to the pronunciation of fluent
Pronunciation:
ˈflü-É™nt
Function:
adjective
Etymology:
Latin fluent-, fluens, present participle of fluere — more at fluid
Date:
1585

1 a: capable of flowing : fluid b: capable of moving with ease and grace (the fluent body of a dancer)2 a: capable of using a language easily and accurately (fluent in Spanish) (a fluent writer) b: effortlessly smooth and flowing : polished (a fluent performance) (spoke in fluent English) c: having or showing mastery of a subject or skill (fluent in mathematics)
— flu·ent·ly adverb

Quite clearly it is possible for many speakers to be less than fluent in their native tongue according to such a definition.

"Quite clearly it is possible for many speakers to be less than fluent in their native tongue according to such a definition."

There are really only two groups of native speakers who might not be considered completely fluent in their own language:

1. Children still at the stage of having the language "inculcated" in them.

2. Persons with mental or physical conditions which impede their ability to speak.

I was assuming definition 2a.

3. People not exposed to the full range of grammatical rules of their native language.

4. People who have gone so long without speaking their language that they have lost fluency.

JJM, you're a real cowboy. Do you just say any ole stuff just to see what kind of reaction you can stir up? Do you REALLY believe that ALL native speakers of a language are of equal fluency, simply by nature of being "native"? That, BY DEFINITION, if someone is a native speaker of a language, then that ALONE makes them maximally fluent? Even if different native speakers have different size vocabularies, breadth of experience, intelligence, education? Are you making up your own definition of the word, fluent (something you seem quite ready to criticize others for, by the way).

All native speakers are "capable of using a language easily and accurately" unless they have some sort of communication problem. If by "accurately" we mean "conforming to the norms of their speech variety." I would disagree with UIP; all native speakers have been exposed to the full range of grammatical rules of their native language; that's what being a native speaker means.

"JJM, you're a real cowboy. Do you just say any ole stuff just to see what kind of reaction you can stir up?"

1. To paraphrase Oscar Wilde, I cannot be initimidated by insults to my web persona.

2. Is there anything wrong with stirring up a reaction? Or should people complacently accept that there are "rules" and if you don't observe them, your English is somehow "incorrect"?

"Do you REALLY believe that ALL native speakers of a language are of equal fluency, simply by nature of being 'native'? That, BY DEFINITION, if someone is a native speaker of a language, then that ALONE makes them maximally fluent?"

Yes, with due consideration for those handicapped and the very young. And drop the unnecessary "maximally"; you're either fluent or you're not.

"Even if different native speakers have different size vocabularies, breadth of experience, intelligence, education?

Yes. These are entirely extrinsic factors that have little or nothing to do with native fluency. All native speakers possess the vocabulary they require to speak; a plumber is no less fluent in his language than a doctor simply because he does not understand a corpus of specialized medical vocabulary. Conversely, is a doctor is less fluent than a plumber because he hasn't got a clue about plumbing terminology? Fluency is based on one's unconscious ability to simply speak in a language; all native speakers can speak their language without a moment's thought about it. That's fluency.

Unless you are suggesting a remote Amazonian tribe, with no writing system and no contact with the outside world, is not fluent in its own language because its vocabulary is "limited" and none of its members have ever visited the Uffizi or attended Harvard.

"Are you making up your own definition of the word, fluent (something you seem quite ready to criticize others for, by the way)."

Oh, I don't know; you would seem to have the edge there on criticism, I'd say.

"It is urgent Molly prepare a revised copy of the file." means, "We urge that Molly prepare a revised copy of the file."
Also note, I am preparing a revised copy of this file :)

"Do you REALLY believe that ALL native speakers of a language are of equal fluency, simply by nature of being "native"? "

It's hilarious that there are actually people out there who find this concept absurd.

Your teacher is right. It's the rare present subjunctive conjugation. No "s" need be necessary.

Which is correct?
1) Art and music save lives
2) Art and music saves lives