1. What is the subjunctive?
Some languages have special verb forms called ‘subjunctive’, which are used especially to talk about ‘unreal’ situations: things which are possible, desirable or imaginary. Older English had subjunctives, but in modern English they have mostly been replaced by uses of should, would and other modal verbs, by special uses of past tenses, and by ordinary verb forms. English only has a few subjunctive forms left: third-person singular present verbs without -tejs, (e.g. she see, he have) and special forms of be (e.g. I be, he were). Except for II he/ she/ it were after if, they are not very common.
See more below:
2. that she see
Ordinary verbs only have one subjunctive form: a third person singular present with no -te)« (e.g. she see). It is sometimes used in that-clauses in a formal style, especially in American English, after words which express the idea that something is important or desirable (e.g. suggest, recommend, ask, insist, vital, essential, important, advice). The same forms are used in both present and past sentences.
- It is essential that every child have the same educational opportunities.
- It was important that lames contact Arthur as soon as possible.
- Our advice is that the company invest in new equipment.
- The judge recommended that Simmons remain in prison for life.
Do is not used in negative subjunctives. Note the word order.
- We felt it desirable that he not leave school before eighteen.
With verbs that are not third-person singular, the forms are the same as ordinary present-tense verbs (but they may refer to the past).
- I recommended that you move to another office.
Be has special subjunctive forms: I be, you be etc.
- It is important that Helen be present when we sign the papers.
- The Director asked that he be allowed to advertise for more staff.
I were and he/ she/ it were, used for example after if and wish in a formal style, are also subjunctives.
- If I were you I should stop smoking.
- I wish it were Saturday. ~
4. fixed phrases
Subjunctives are also used in certain fixed phrases. Examples:
- God save the Queen! Long live the King!
- God bless you. Heaven forbid.
- He’s a sort of adopted uncle, as it were. (= … in a way.)
- Be that as it may … (= Whether that is true or not … )
- If we have to pay £2,000, then so be it. (= We can’t do anything to change it.)
5. other structures
Most subjunctive structures are formal and unusual in British English. In that clauses, British people usually prefer should + infinitive, or ordinary present and past tenses.
- It is essential that every child should have the same educational opportunities. (OR … that every child has … )
- It was important that lames should contact Arthur as soon as possible. (OR … that lames contacted … )
Source: Practical English Usage by Michael Swan