In the Glossary of Terms attached to the UK's National Literacy Strategy it says this about the subjunctive (as I learned from a useful and appropriately scathing post on Michael Rosen's blog):
The subjunctive form of a verb is occasionally used in very formal contexts to indicate unreality, uncertainty, wish, emotion, judgement, or necessity. Its inflection is complicated, because it does not always differ from nonsubjunctive forms.
What an unbelievable piece of outright burbling nonsense.
Here is an example of the subjunctive construction, using the verb walk:
It is essential that he walk at least half an hour each day.
Now for that complicated inflection you were warned about; brace yourselves:
So the subjunctive always uses a form identical to the non-3rd-singular present tense. This holds for all verbs, with a single exception: There is one irregular verb where in subjunctives the form is different from any of the present-tense forms, if you can bear to contemplate such a thing. That verb is be. Here is its highly complicated paradigm:
So the business about the inflection being complicated is just idiocy.
And what about that helpful explanation of the meanings expressed? Unreality, uncertainty, wish, emotion, judgement, necessity? I hope that was really helpful to you. But I don't know what the hell they're talking about. It is easy to see for all of these vague meaning-based categories that they do not in general trigger use of the subjunctive:
unreality: *It would be totally unreal that he win a medal.
uncertainty: *I am really not sure that he win a medal.
wish: *I hope he win a medal.
emotion: *Fuck, I'm so mad that he win a medal!
judgement: *In my considered opinion, he win a medal.
necessity: *There is no conceivable situation where he not win a medal.
The people who wrote the glossary entry simply have no idea what they're talking about in connection with the subjunctive construction itself.
In addition, in a familiar mistake that is found in most traditional grammars, they have confused the very restricted irrealis form were (as in I wish I were a monkey) with the quite differently limited subjunctive, which has nothing to do with it. They call the irrealis were the past tense of the subjunctive form. Clueless.
I really worry about my subject. In science, teachers aren't always brilliant experts, but generally the chemistry teacher knows that osmium isn't made of chlorine. In grammar, you can't count on even basic competence of that sort in the people who devise the national curriculum.
As Mark Liberman has so often pointed out here on Language Log, it's our fault: We linguists have work to do. In a hundred years of the scientific study of linguistic structure (I'm counting from when Ferdinand de Saussure had given all the offerings of his "Course in General Linguistics") we haven't succeeded in getting even a modest amount of sensible classification and terminology into the teaching of grammar in the schools.
The UK National Literacy Strategy is a disgrace (and I am pleased to hear the rumors that the present government is thinking of ditching it); but we linguists are at fault for not riding herd on them better.
[I don't know why, but I just felt it was vital that comments be closed.]