E Some people have it easy. When their kids ask them what they do at work, they can give a simple, direct answer: “I put out fires” or “I teach primary school”. As a theoretical physicist, I never had this luck. Society has come to expect many things from the physicists. It used to be that we only had to discover the basic laws of the world and supply the techniques that would power the next Silicon Valley. With these expectations we were fairly comfortable: they are the sorts of things we think we know how to do. What makes us uncomfortable and what makes it hard for us to tell our kids what we’re up to is that in this century we have become, though unwillingly, gurus on questions such as “What is the nature of Reality?” We now deal with a whole new class of problems. We ask how the world began and what the nature of matter is. The answers we are coming up with are just not easy to comprehend for the average person. So, when physicists get out of their cars in the morning, have a cup of coffee and sit down in front of their computers, they leave a familiar world and enter a place where things act in strange ways that are impossible for ordinary people to understand. 72. According to the passage, in a way physicists are . A. honest        B. comfortable    C. strange        D. unlucky 73. By what the writer says about physicists, we know that physicists . A. don’t like their careers B. live in two different worlds C. are coming up with new answers to old questions D. don’t have to tell people what they are doing 74. From the passage we can conclude that theoretical physicists . A. contributed to the new industry in Silicon Valley B. only have to answer the basic questions about the world C. have disappointed the expectations of many people D. have found it hard to make themselves popular 75. What’s the main idea of the passage? A. Society seems to know a bit about physicists’ work. B. Most people are expecting to know what physicists are doing. C. Physicists are doing more and more difficult jobs. D. It’s impossible for average people to know physicists’ work.