Keene contacted Figueroa on Facebook when the pay-it-forward chain came out in the local news.She revealed that she was the "mystery customer" that started the long chain of kindness.

　　Keene added that she was surprised by the number of people who continued her good deed when she was only trying to brighten someone's day.

25. Who started the pay-it-forward chain?

　A.Torie Keene from Lakeland.B. Marisabel Figueroa.

　C. Manager of a McDonald's. D. Father Christmas.

26. What're the drivers' reactions towards the generous behavior?

　A. Lucky and unbelievable.B. Funny and surprised.

　C. Amazed and moved. D. Ridiculous and happy.

27. For how long did the chain last?

　A. A week. B. A whole day.

　C. About twelve hours. D. About six hours.

　　In March, federal officials gave Amazon permission to test its drone delivery plan. But even with a patent and the ability of drones to make deliveries, it does not appear they will put its new delivery system in place any time soon. The U.S. Patent Office published the document. It describes Amazon's plans to use the Global Positioning System, or GPS, to deliver products to homes and to wherever people are.

　　The drone will use a customer's mobile device-usually a smart phone-to avoid hitting people or buildings and to identify a safe area to land. The company wants to deliver products within 30 minutes of people ordering them on its website.

　　Amazon is not yet offering drone delivery. But Professor Alkalay says it will not be long before it does. "I do think that in the reasonable future they're going to start doing deliveries. We already see deliveries being done in disaster areas, in remote areas. I think there's huge demand for that type of delivery."

　　Professor Alkalay says there are concerns that the drones will crash into objects or people, or that the products and drones will be stolen or intentionally damaged. But she says that is because many people believe the drones would only deliver the products to the front door of a house. "If you think of drone delivery perhaps to your rooftop, then you would have an opportunity to separate the pedestrian and the vehicular traffic, and at the same time separateit from air traffic."

Professor Alkalay notes that American homes are not currently able to receive deliveries on