The Subjunctive expresses doubt, uncertainty, hope, fear, possibility or personal opinions. It barely exists in present day English but it frequently used in Italian. It has four forms: two simple tenses ( Present Subjunctive and Imperfect Subjunctive) and two compound tenses ( Perfect Subjunctive and Pluperfect Subjunctive). A compound tense contains the subjunctive of an auxiliary verb ("essere" or "avere") followed by the past participle of a verb. It is mainly used in dependent sentences that are introduced by che. It is also useful to remember that there is a large range of expressions that demand the subjunctive. The most common ones are before, provided that, although and even though.