Use a subject and the base form of a verb after the word "that" to express contingency or unlikeliness in a subjunctive construction. Some base forms of verbs are "be," "see," "swim" and "laugh." For example, "He asked that we laugh less loudly" and "The philosopher proposed that materiality be despised."
Use the past subjunctive of the verb "to be," which is "were," after "if" to describe or express a hypothetical condition in a subjunctive construction. For example, "If wishes were horses, beggars would ride" and "If I were wrong, you would be right."
Form a past subjunctive just as you form a past indicative. For example, "Would that she sang as marvelously as she dressed," in which "sang" is the simple past subjunctive of "to sing"; and "If only he had given me a million dollars!" in which "had given" is the past perfect subjunctive of the verb "to give."
Use a subject and the base form of a verb after the word "let" to express a wish or granted permission for a certain act or event. For example, "Let the fun begin!" and "Let the subjunctive not vanquish you!"