Supermarkets use automatic checkout machines because they ______. A: add to the pleasantness of shopping B: show the development of technology C: can thrill the customers at times D: increase the stores’ efficiency

Apart from its advantages, travel also has it ____1_____, which make us not take great pleasantness. More often than not, we need a ____2_____ after our vacation. We travel because we need to , because distance and difference are the ______3_______ of creativity. Travel will change our mind to some extent, which in turn can have ___4_____ on everything in our life.