现在很多学生早餐是一瓶纯牛奶加鸡蛋，从合理膳食角度来说，这种早餐主要是缺乏 ．（填一种营养成分）
糖类
题目分析：此题考查的是早餐的合理膳食．青少年正处于生长发育时期，应食足够的糖类、适量的蛋白质、一定量的水、无机盐、脂肪、维生素，以保证正常的生长发育．合理科学膳食，不偏食．结合题意，据此解答．
青少年正处于生长发育关键时期，每天保持合理的营养格外重要．应食用足够的糖类以维持各项生命活动，食用适量的蛋白质以满足身体生长发育的需要，还应食用一定量的水、无机盐、脂肪、维生素，以保证身体的正常生长发育和生理活动．合理科学膳食，不偏食．题中的早餐是一瓶纯牛奶加鸡蛋，牛奶和鸡蛋主要提供的是蛋白质和钙，该早餐主要是缺乏糖类．
故答案为：糖类．
点评：解此题的关键是理解掌握食物中的几种成分的主要作用．青少年正处于生长发育时期，应食足够的糖类、适量的蛋白质、一定量的水、无机盐、脂肪、维生素，以保证正常的生长发育．
| 阅读理解。 |
| People are busy working every day, so they do not have enough time to do exercises. As a result (结果), many people become too fat. To keep our bodies healthy, we have to do exercises every day. There are many kinds of exercises. Bending (弯腰) and stretching (伸展) help us move easily. Before we play ball games or swim, it is better for us to do bending and stretching exercises first. This kind of exercise is sometimes called"warm-up exercise". Running is also a good exercise. If we cannot run fast, we can jog. Jogging means running slowly. Before we run or jog, we must do warm-up exercises. And we should not run or jog in busy streets. The air there is often dirty. Some people like weightlifting (举重) because it can make their bodies strong. We also need to do some warm-up exercises before weightlifting. |
| 1. _____ makes many people too fat. |
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| A. Eating or drinking every day B. Having no time to do exercises C. Doing more exercises D. Reading at home |
| 2. Before we _____, we must do warm-up exercises. |
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| A. run B. jog C. work D. Both A and B |
| 3. _____ is called "warm-up exercise". |
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| A. Playing ball games B. Swimming C. Bending and stretching D. Weightlifting |
| 4. Why do people like weightlifting? |
[ ] |
| A. Because it can make them work well. B. Because it can make them thin. C. Because it can make their bodies strong. D. Because they don't like other exercises. |
| 5. Which of the following sentences is RIGHT according to the passage? |
[ ] |
| A. Jogging means running quickly. B. Busy streets are not good places for running. C. Weightlifting can help us move easily. D. We shouldn't do warm-up exercises before swimming. |