Background music may seem harmless, but it can have a powerful S36 ______ on those who hear it. Recorded background music first S37 ______its way into factories, shop and restaurants in the US. But it soon S38 ______to other parts of the world. Now it is becoming S39 ______difficult to go shopping or eat a meal without listening to music. To begin with, "muzak" (音乐广播网) was S40 ______ simply to create a soothing (安慰) atmosphere. Recently, however, it’ s become big business -- thanks in part to recent research. Dr. Ronald Milliman, an American S41 ______expert, has shown that music can S42 ______sales or increase factory production. But, it has to be light music. A fast one has no effect at all on sales. Slow music can increase receipts by 38%. S43 ______. Yet, slow music isn’t always the answer. Dr. Milliman found, for example, that S44 ______. So S45 ______. S45