From a rhetorical point of view, sentences are loose, periodic, or balanced.
I. loose sentence and periodic sentence1. A loose sentence puts the main idea before all supplementary information; in other words, it puts first things first, and lets the reader know what it is mainly about when he has read the first few words. The reverse arrangement makes a periodic sentence: the main idea is expressed at or near the end of it, and it is not grammatically complete until the end is reached. The re ...