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阅读理解 There are several advantages in planting trees: they firm the soil, soak(渗透) up extra water and take carbon dioxide out of the atmosphere. However, it now turns out that planting trees could add to global warming. We all know that tree roots do a great job of keeping soil firmly on the ground and out of the wind's power. The problem is that some of the dust clouds play an important part in soaking up carbon dioxide. Huge dust storms blow out over the oceans from dry parts of North Africa and Central Asia. Tons of dust are lifted and left as a thin film over the ocean surface. Dust from China is carried east and left in the Pacific Ocean. If a tree planting programme there is successful and the dust supply reduced, the net result may be that less carbon dioxide gets locked away in the ocean. Andy, an environmental scientist has spent the past few years studying dust and says his work shows clearly the complexity of the system. For this reason the need is to focus on cutting carbon dioxide giving off rather than doing anything else. Robert, an American scientist, has shown that when native grassland areas are invaded by trees, carbon is lost from the soil. 'We are studying why the soil carbon disappears, but one theory is that trees do a lot more of their growing above ground compared to grass, so less carbon goes directly into the soil from trees.' said Robert. In wet areas of the world, the gain from trees absorbing carbon dioxide above ground seems to be outweighed by the loss of carbon from the soil below ground. Countries that plan to fight against global warming by planting trees may have to think again. Solutions to environmental problems are often more complex than they first appear, and understanding the Earth's climate is a very great challenge. 1. People usually hold the opinion that________. A. huge dust storms can destroy carbon dioxide B. planting trees could reduce global warming C. huge dust storms can destroy the oceans on the Earth D. planting trees is the only way to control huge dust storms 2. Andy, an environmental scientist, believes that________. A. environmental problems are more complex than expected B. trees shouldn't have been planted in dry places C. dust plays a more important part than trees D. carbon dioxide is harmful to everything 3. Robert's experiment proves that________. A. trees absorb more carbon than grass B. carbon can turn grass into dust C. less carbon can make trees grow faster D. grassland areas should be covered by forests 4. The best title for this passage is '________'. A. The importance of planting trees B. The dust clouds soak up carbon dioxide C. Is it really useful to plant trees to reduce global warming? D. Why the soil carbon disappears
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【单选题】卵巢功能不全和闭经宜选用下列哪种药物治疗
A.
双醋炔诺醇
B.
氯地孕酮
C.
黄体酮
D.
甲睾酮
E.
己烯雌酚
【单选题】卵巢功能不全和闭经宜选用下列哪一药物治疗:
A.
氯地孕酮
B.
甲睾酮
C.
己烯雌酚
D.
双醋炔诺酮
E.
黄体酮
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【多选题】松树分泌松脂的主要目的包括:()
A.
防御
B.
杀灭有害细菌
C.
吸引昆虫
D.
排毒
【单选题】治疗卵巢功能不全和闭经,选用( )
A.
己烯雌酚
B.
苯丙酸诺龙
C.
炔诺酮
D.
甲睾酮
E.
强地松龙
【单选题】以下对信息特征的描述错误的是?()
A.
时效性
B.
变换性
C.
易用性
D.
时效性
【单选题】水刷石表面脏,颜色不一致的原因是()。
A.
表面没有抹平压实
B.
原材料未一次配齐
C.
配合比不准确
D.
以上都不是
【多选题】现行《中华人民共和国企业所得税法》规定的企业所得税的税收优惠方式包括( )。
A.
加计扣除
B.
加速折旧
C.
减计收入
D.
税额抵免
【单选题】设一个平而透射光栅的缝宽为a,缝间隔为d,总缝数为N,以波长为 的光垂直入射。当光栅缝间隔d减小时,则( )
A.
光栅的色散本领提高,因此其分辨本领也随之提高
B.
光栅衍射图样中的亮纹变细
C.
两亮纹之间的间隔增大
D.
缺少的亮纹级次不变
【简答题】当重力式挡土墙抗滑稳定性不满足时,应采取哪些工程措施?
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