In 2017 an American appeal court had to decide what a single sentence meant, and about five million dollars turned on the answer.
A state law listed the kinds of work that do not earn overtime pay. Seven of them were plain enough — canning, processing, preserving, freezing, drying, marketing, storing — and then the list ended: packing for shipment or distribution. Read one way, that last item is two separate activities — packing, and also distributing. Read the other way, it is one: packing, done for either shipment or distribution.
The drivers who brought the case did not pack anything. They only drove. If the phrase named two activities, their work was on the list and their overtime was gone. If it named one, they had been underpaid for years.
Nothing in the sentence settled it. The court noted that a comma before the last item would have made the two-activity reading plain, and that the comma was not there. It ruled for the drivers, and the company later settled for about five million dollars.
The lesson is not about punctuation. It is that an English sentence can carry two structures at once, and that the reader — not the writer — is the one who has to notice. Exam questions are built by people who know this. When a sentence is ambiguous, slow down and write out both readings before choosing one.