The Period [.].—Declarative and imperative sentences, when not connected in construction with what follows, are closed by periods.
Examples:—The child is father of the man.
Examples:—The king is dead, long live the king.
A period should be placed after every abbreviation. The period thus used is part of the abbreviation.
Examples:—Wash., Washington; Gen., General; Pro tem., pro tempore, for the time being; Esq., Esquire; Gov., Governor.
Such expressions as 3d, 18th, 8mo, are not abbreviations and do not require a period after them.
A period should always be placed after the Roman numerals.
Examples:—I., II., III., IV., V., VI., VII., VIII., IX., X., etc.
Interrogation Point [?].—The interrogation point is used for marking all questions. When the question consists of several parts, or when several questions are contained in one sentence, there is some difficulty in deciding whether there should be one or more interrogation points. The principle is that if one answer is sufficient for all, one point is enough; if different answers are required, a point should be placed after each question.
Examples:—What can I do for you?