A cumulative sentence (or “loose sentence”) is one that starts with an independent clause, but then has additional or modifying clauses. They’re often used for contextual or clarifying details. This may sound complex, but even, “I ran to the store to buy milk, bread, and toilet paper” is a cumulative sentence, because the first clause, “I ran to the store,” is a complete sentence, while the rest tells us extra information about your run to the store. Example: “It was a large bottle of gin Albert Cousins had brought to the party, yes, but it was in no way large enough to fill all the cups, and in certain cases to fill them many times over, for the more than one hundred guests, some of whom were dancing not four feet in front of him.” – Commonwealth, Ann Patchett