题目内容：
根据以下短文，回答题。Going on a diet
A typical person needs about 1, 800 calories per day to stay alive. These calories keep your heart beating and your lungs51. They keep your organs operating properly and your brain running. They also keep your body52. A person gains weight because he or she consumes more calories per day than needed. The only53to lose fat is to reduce the number of calories that you consume per day. This is the basic principle54going on a diet. Unfortunately, diets don’t55for most people. They do lose weight but then go off the diet and put it back. Building a56diet and exercise plan is the key to maintaining a57weight. You need to58how many calories you need in a day and how many you actually59. The next step is to60exercise so that you can raise the number of calories you can consume per day. Exercise61can show you how many calories different forms of exercise can burn. Burning 250 or 500 calories per day can make a big62. You can ride an exercise bike while you are watching TV or you can climb the stairs instead of the elevator. Find an exercise partner. Exercise can be a lot63if there is someone to talk to. It’s a good idea to wear64clothes if you are on a diet. Tight clothing acts as a reminder of what you are trying to65.
A．running B．breathing C．operating D．working
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