Read this paragraph.The students of Valencia High adore the school vending machine. It has been in operation as long as the school, providing a variety of snacks, from crackers to granola bars to juices and even fresh fruit. These snacks sustain students throughout the day and help them ward off hunger during after-school activities. The teachers and custodians are not as enthusiastic. They complain about the wrappers, containers, and peelings that litter the floors and hallways. Many staff members believe that a trial period should begin in which students must prove that they can keep the school clean or lose the privilege of the vending machine.