How Much to Tip You’re out to dinner . The food is delicious and the service is fine . You decide to leave a big fat tip . Why ? The answer may not be as simple as you think .Tipping , psychologists have found , is not just about service . Instead , studies have shown that tipping can be affected by psychological reactions to a series of different factors from the waiter’s choice of words , to how they carry themselves while taking orders , to the bill’s total . Even how much waiters remind customers of themselves can determine how much change they pocket by the end of the night .“Studies before have shown that mimicry brings into positive feelings for the mimicker ,”wrote Rick van Baaren , a social psychology professor . “ There studies show that people who are being mimicked become more generous toward the person who mimics thorn .” So Rick van Baaren divided 59 waiters into two groups . He requested that half serve with a phrase such as “ Coming up ! ” Those in the other half were instructed to repeat to orders and preferences back to the customers . Rick van Baaren then compared their take home . The results were clear－it plays to mimic your customers . The copycat waiters earned almost double the amount of tips to the other group . Leonard Green and Joe Myerson , psychologists at Washington University in St . Louis found the generosity of a tipper may be limited by his bill . After research on the 1,000 tips left for waiters , cab drivers , hair stylists , they found tip percentages in these three areas dropped as customers’bills went up . In fact , tip percentages appear to plateau when bills topped ＄100 and a bill for ＄200 made the worker gain no bigger percentage tip than a hill for ＄100 . “That’s also a point of tipping ,” Green says . “ You have to give a little extra to the cab driver for being there to pack you up and something to the waiter for being there to serve you . If they weren’t there you’d never get any service . So part of the idea of a tip is for just being there .” 1.How many factors affecting the customers’ tipping are mentioned in the passage ? A.1                              B.2                              C.3                              D.4 2.These studies show that ______. A.tipping can be affected by physical reactions to many different waiter’s factors B.people who are being mimicked usually tip less to the person who mimics them C.the mimic waiters can get almost twice as much money as the other group D.mimicry makes the mimicker feel bad 3.According to the passage , which of the following will be likely to show the right change of the tip percentages ? 4.We know from the passage that the writer seems to ______. A.object to Mr Green’s idea about tipping B.think part of Mr Green’s explanation is reasonable C.give his generous tip to waiters very often D.support the opinions of Mr Green and Rick van Baaren about tipping