1Shаkespeаre wrоte thаt “all the wоrld’s a stage.” 2He meant that everyоne has at least one part, or role, to play in life. 3In fact, every role we play has an “on stage” and a “backstage” area; in the first area, we’re on our best behavior; but in the second area, we can “let our hair down.” 4For example, in the dining room, a waiter is “on stage.” 5No matter how rushed he is or how annoyed he feels, a waiter is expected to be polite and helpful to his customers. 6Once he returns to the kitchen, however, it’s another matter. 7There he is “backstage” and can let his true feelings show. 8In the kitchen, the waiter can make sarcastic remarks about the customers or even joke about serving a plate of food that’s been dropped. Write the number of the sentence that states the main idea of the paragraph.