The subjunctive mood (sometimes called conjunctive mood) is used a lot less than the imperative and indicative in English. In fact if you learn British English you can spend a lifetime avoiding it if you want to. Most native speakers do.
It's easy to miss the subjunctive, because the form of the verb is usually the same as it is for the indicative, apart from the verb 'to be' and the subjunctive for the present tense third person singular, which drops the -s or -es.
The subjunctive is typically used after:-
- the verbs: ask, command, demand, insist, propose, recommend, request, suggest
- the expressions: it is desirable, essential, important, necessary, vital
- if, as if, and wish
I suggest you reconsider.
It is essential that she hand in her homework on time.
The subjunctive mood is used to express unreal situations; wishes, hypothetical situations etc.
I wish I had more time to spend online.
The verb that causes the most problems in the subjunctive mood is the verb 'to be'. In the subjunctive we use 'be' in the present tense and 'were' in the past tense, regardless of the subject.
If I were rich I would buy a caravette and travel round the world.
If he were rich he would buy a caravette and travel round the world.
If they were rich they would buy a caravette and travel round the world.
The best example of the subjunctive mood is the song "If I were a rich man" from the musical "Fiddler on the roof".
The reason for the decline of the subjunctive in British English is that we prefer to use modal verbs. The modal auxiliaries do not have present subjunctive forms, but if I were you, I wouldn't worry about it too much.