Writers often inadvertently create confusion by placing "only" incorrectly in a sentence. It should go immediately before the word or phrase which it modifies. "I lost my only shirt" means that I had but one to begin with. "I lost only my shirt" means I didn't lose anything else. "Only I lost my shirt" means that I was the only person in my group to lose a shirt. Strictly speaking, "I only lost my shirt" should mean I didn't destroy it or have it stolen--I just lost it; but in common speech this is usually understood as being identical with "I lost only my shirt." Scrutinize your uses of "only" to make sure you are not creating unwanted ambiguities.
List of errors