The maxims of quantity and relation are at work in B's response, like principles guiding our indicative interpretation of the fragment. Sometime after dinner. T he interrogative mood signals the speakers' desire for information, that they are asking a question, that they are 'interrogating' the listeners. The interrogative is marked by starting a clause with an auxiliary verb or an interrogative pronoun. T he imperative mood express the speakers' sense of a command, request, or exhortation - an imperative.
Speakers signal the imperative mood by using a base form of the verb in clause-initial position.
T he subjunctive mood express the speakers' sense of the unlikely, a wish, a prayer, a hope. The subjunctive describes the state of affairs as speakers wish or hope them to be. Speakers signal the subjunctive by beginning subordinate clauses with an auxiliary or by using subordinators that overtly mark hypothetical conditions. Base forms of verbs can also signal the subjunctive. F inally, the base form is also used in several older, formulaic subjunctive expressions that have survived in the modern language.