@TheYellowRobot - I've realised that we can also have a result clause with just an auxiliary and no main verb, but in this case we couldn't invert the subject and auxiliary:

'John signed up for dance classes, and so did Marie.' - adverb 'so' - inversion - meaning simply 'and Marie did (so) too' - no idea of cause and result.

'John signed up for dance classes, and so Marie did too.' - conjunction 'so' - no inversion - meaning - 'therefore, Marie did too.' - result clause.

@TheYellowRobot - some people make silly typos, and so do I, apparently. Sorry for getting your name wrong, and Rider Haggard's, for that matter.

@TheYellowRabbit - 'John loves to dance and so does Marie' sounds a lot better to me than 'John loves to dance, and Marie loves to dance.' which has unnecessary repetition and sounds unnatural (who would say it?). In fact we teach our EFL students to use 'so do/does' in cases like this - this is known as substitution.

There is only one conjunction here - 'and'. In the sentence 'And so we went to bed', 'so' is indeed a conjunction, followed by a full verb. But in 'and so does Marie' etc, 'so' is an adverb followed by the auxiliary verb 'does', which replaces 'loves to dance' (substitution).

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Adverb + auxiliary + noun / pronoun

As to its propriety, the expression 'and so do / doth' + pronoun was used at least twelve times by Shakespeare, including:

"You love sack, and so do I;"
"My hair doth stand an end to hear her curses". - "And so doth mine."
"She for an Edward weeps, and so do I:"

'and so did' + noun / pronoun appears in several classics:

"and with that I fired again among the amazed wretches, and so did Friday", Defoe, Robinson Crusoe

"Then every body got down; and so did Mr. Thornton", Mrs Gaskell - North and South
"And King Arthur set his love greatly upon her, and so did she upon him", Thomas Malory - Le Morte d'Arthur

"She passed through, and so did Bougwan, and so did I", Henry Riuder Haggard - King Solomon's Mines

It also appears frequently in quality publications:

"Disposable income grew twice as fast as the economy in the 2000s, and so did consumption" - The Economist

"Crucially, the debt-ceiling agreement remains in place, and so do the two trillion dollars plus of budget cuts it entails." - The New Yorker

"For 36 days after the election, the results in Florida remained in doubt, and so did the winner of the presidency." - Washington Post

And it also appears in academic papers (found through Google Scholar)

"Non-smokers married to heavy smokers had an increased risk of lung
cancer, and so did subjects whose mothers smoked"

"Tom Paine and Condorcet used them to the end, and
so did the authors of the French Declaration of the Rights of Man"

"toxicity declined and so did the number of identified
allelochemicals detected in the mixture of soil and residues"

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Double conjunction + clause

And here are a couple with the double conjunction (notice the full verbs - 'did not preclude' and 'did not profit'):

"A defendant's consent to a confiscation order which had been given under a mistake of law was not binding and so did not preclude an appeal " - The Times

"He made the invention in 1892 but failed to get a patent and so did not profit from his ingenuity." The Independent

And some double conjunctions from academic papers:

"We made fewer comparisons and so did not need to adopt
such stringent measures"

"However, it is at least a possibility that non-respondents just
did not experience any of the listed physical responses to music, and so did not
consider it worth their while to co-operate with the research"

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It doesn't look to me as though you have anything to worry about with your students.

Finally, I don't think there's any necessity to use a comma before a coordinating conjunction when both clauses are as short as thee ones in your example sentence are.

@jayles - Yes, I checked out Google Books for this occurring in 18th and 19th century books, and few books carried possessive apostrophes of any kind before the 19th century. The great irony, of course, is that apostrophes were probably being used to show plurals of foreign words, the origin of today's 'greengrocer's apostrophe', before they were used for possession.

@sundy - we'll have to agree to differ. On a particular occasion like this where there is a real possibility of winning, we'd normally use what in EFL and ESL teaching we call First conditional, with a present tense after if, and will (or an imperative or certain modals) in the result clause. If I'm not so sure about my course of action I'd use 'could, may' or 'might', but not 'would'. The only time I would use 'would' in the result clause of a real conditional is to be more polite - "If you're ready, would you follow me, please?" or if the verb in the if clause shows uncertainty, as in the conditional sentence I just wrote "I'm not so sure ...". "If I've won" or "If I won" (with real past meaning) show no such uncertainty.

However, as the possible number of conditional structures is unlimited it's probably theoretically possible to come up with any interpretation. I'm really only interested in how conditionals are used in everyday life, not weird and wonderful scenarios where the interpretation is stretched to the limit, so as they say on 'Dragon's Den', I'm afraid I'm out.

@sundy - " Ideally, it would be perfect if we could create a subjunctive form of verb for every verb in English" - that would be to reverse history and go against what you were saying earlier. In fact these forms do/did exist, but over the centuries they've been replaced by indicative forms. English has been gradually ridding itself of the subjunctive since it stopped being Anglo-Saxon. Present subjunctive - "It's vital that he be informed" is very rarely used in British English, for example, except in very formal writing. All we have left are a few vestiges - a few fixed phrases and 'were'.

So, no, it wouldn't be perfect; it would be totally artificial and totally unnecessary. The beauty of the English verb system is that each verb has a maximum of five inflections, for example - 'do, does, did, done, doing'. All the rest is done with auxiliaries.Why then go and complicate matters? We express doubt or indefiniteness etc in other ways. For example 'We're looking for someone who speaks French' - in Spanish that would need the subjunctive - but there's no reason why we have to have it in English.

@sundy - 'If I won the lottery, I'd buy a new house' with present meaning describes a hypothetical condition. But you're talking about a specific occasion, so If I hadn't had a chance to check my ticket the previous night, I'd never say to my wife 'If I won the lottery, I'd buy a new house' but 'If I've won the lottery, I'll buy a new house'.

Well, we would in British English at least. I know Americans don't use present perfect as much as us, but if it's a real condition, you'd (they'd) still use 'will' in the result clause.

If + past simple + will is perfectly possible when talking about a real possibility on a specific occasion but when you don't know if the past condition has been fufilled - "If he managed to finish that report last night, we'll be able to get it to everyone today".

@sundy - I think you're confusing linguists and grammarians - grammar books written by linguists, for example the Comprehensive Grammar of the English Language (CGEL), by Quirk and Greenbaum, and the Cambridge Grammar of the English Language (CaGEL), by Huddleston and Pullum, are entirely descriptive and allow both 'If I were prime minister' and 'If I was prime minister', both being what CaGEL calls Irrealis (i.e. Unreal past).

Linguistics is the study of language as it is, not language as how some people think it should be. That's the domain of the prescriptivists: people like Neville Gwynne. Modern linguistics is based almost entirely on corpora - computerised collections of real language, both written and spoken, such as the British National Corpus and COCA - The Corpus of Contemporary American English.

@Jasper - It's OK, I wasn't suggesting you were responsible for his views. The 'shtr' thing is way outside my experience (I don't think I've heard it on British radio, apart from Sir Sean), although you might well be right about its source. Which is why I noticed the 'literally' remark, and found it interesting. But nothing, I admit, to do with the matter in hand.

Actually Mona's example of "temp-a-chur" is also quite interesting, as most of us don't pronounce all the syllables of that either - /tɛmp(ə)rətʃə/ (Oxford Online) - i.e. "tempr-a-cher" (and that goes for both BrE and AmE).

@sundy - OK, I follow your example now, but I think you're stretching it a bit far. In fact what I'd say in that context is something like: "If he really did act like that, I'd throw him out if he came again."

However, I've realised that there is another possible interpretation of "If he acted like that at my party, I'd throw him out" and that is where we use would for repeated actions in the past, for example - "I used to live near my work and would walk to work every day"

So it would be possible to interpret "If he acted like that at my party, I'd throw him out" as "Whenever he acted like that, I used to throw him out". But as you say, context would usually help you.

So here's another one:

"If I won the lottery, I'd buy a new house" - can you put a different interpretation on that?

My point, though, is that Unreal past (subjunctive, for those who prefer it) is exactly the same as Real Past for all verbs except one, and for only two persons of that one verb, 1st and 3rd singular of 'be'. I can seen no logical reason why a different form is thought necessary for those two persons of one verb when we have absolutely no confusion in all other cases. It might sound more refined, but that's about all.