阅读下面短文,按照句子结构的语法性和上下文连贯的要求,在空格处填入一个适当的词或使用括号中词语的正确形式填空,并将答案填写在答题卡标号为41-50的相应位置上。
Background music may seem harmless, but it can have a powerful effect on those     41    
hear it.     42     (record) background music first found    43    way into factories, shops and restaurants in the United States. But it soon spread to other parts of the world. Now it is becoming     44     (increase) difficult to go shopping      45     eat a meal without listening to music.