Most sentences can be classified as either loose (or cumulative) or periodic.
The loose (or cumulative) sentence is our common means of expression. We begin with a subject, followed by an action (the verb), and then additional details.
"Sam, our class president, hopes to attend Harvard University this fall."
The loose (or cumulative) sentence presents the subject and verb near the beginning, such that the reader knows who or what is being discussed and what is happening.
The periodic sentence is a suspended sentence; in other words, the reader either does not know who or what is being discussed and/or what is happening until the final word of the sentence. Well-crafted periodic sentence hold the reader in suspense. The reader anticipates something important, but writer holds it back, building tension, until the final moment of revelation. In the following examples, the actual completed sentence is underlined. Note how the writers begin with a series of phrases or clauses, establishing the scene or situation prior to the main statement:
"Years and years ago, when I was a boy, when there were wolves in Wales, and birds the color of red-flannel petticoats whisked past the harp-shaped hills, when we sang and wallowed all night and day in caves that smelt like Sunday afternoons in damp front farmhouse parlors, and we chased, with the jawbones of deacons, the English and the bears, before the motor car, before the wheel, before the duchess-faced horse, when we rode the daft and happy hills bareback, it snowed and it snowed." (Dylan Thomas, A Child's Christmas in Wales)
“Out of the bosom of the Air, Out of the cloud-folds of her garment shaken, Over the woodlands brown and bare, Over the harvest-fields forsaken, Silent and soft, and slow, Descends the snow.”
(Henry Wadsworth Longfellow, "Snowflakes") While he was declaring the ardour of his passion in such terms, as but too often make vehemence pass for sincerity, Adeline, to whom this declaration, if honourable, was distressing, and if dishonourable, was shocking, interrupted him and thanked him for the offer of a distinction, which, with a modest, but determined air, she said she must refuse. (Ann Radcliffe, Romance of the Forest)
