根据下面一段文字，概括说明什么是“低碳经济模式”（不超过30个字）。
经济发展中，人类大量消耗化学能源，能源利用效率低下，能源结构不合理，大量排放二氧化碳，破坏了地球生物圈的碳元素平衡，加快了气候变暖的进程，引起全球气候灾害性变化。在此背景下，“低碳经济模式”的概念产生了。
“低碳经济模式”指：_________________________________________
能源利用效率高、能源结构优化、低能耗、低排放的环保经济模式。（答案要点不论排序，亦不要中心词“环保经济模式”）
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| Is food important for us? The answer is YES. If we do not eat 1 , we will feel hungry. If we can not find food when 2 are hungry, we may feel very 3 . Maybe we can become sick, then die later. Now we have another problem, if we eat, what kind of food is 4 for us? Is meat better than vegetables and fruits? 5 vegetables and fruits 6 than meat? For some people, it is very easy to answer this 7 : Vegetables and fruits are surely(一定) better than meat, because they 8 eat meat. For most of us, it is not very easy to decide on 9 is better. Doctors say it is not really important for us to decide on which is better, meat or vegetables and fruits, but it is 10 to take a balanced diet of meat and vegetables and fruits. | |||
| ( )1. A. water ( )2. A. we ( )3. A. calm ( )4. A. good ( )5. A. Are ( )6. A. cheaper ( )7. A. problem ( )8. A. always ( )9. A. which ( )10. A. interesting | B. milk B. you B. bad B. expensive B. Or B. better B. question B. usually B. who B. popular | C. food C. they C. happy C. cheap C. And C. more expensive C. problems C. often C. why C. important | D. medicine D. people D. quiet D. bad D. Or D. more awful D. questions D. never D. how D. unhappy |