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问题 选择题

深圳经济特区建立30年来，从一个3万人的边陲小镇快速崛起为一座承载人口超过1400万的现代化大都市，创造了世界工业化、城市化发展史上的奇迹。你认为发生上述变化的主要原因是

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①坚持以经济建设为中心，大力发展社会生产力

②坚持走改革开放的发展道路

③发扬了艰苦奋斗、开拓创新的精神

④实现了全面建设小康社会的奋斗目标

A．①②③        

B．①③④        

C．②③④          

D．①②④

答案

答案：A

单项选择题

男性，45岁。腹泻2d，每天10次左右，稀便，伴发热。第2d感腹痛，大便混有脓血伴里急后重，以下哪项诊断可能性最小

A．细菌性痢疾

B．阿米巴痢疾

C．侵袭性大肠杆菌肠炎

D．成人轮状病毒肠炎

E．空肠弯曲菌肠炎
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单项选择题

Nuclear fusion is a process whereby the nuclei of atoms are joined, or "fused," and in which energy is released. One of the by-products of fusion is helium-4 gas. A recent fusion experiment was conducted using "heavy" water contained in a sealed flask. The flask was, in turn, contained in an air-filled chamber designed to eliminate extraneous vibration. After the experiment, a measurable amount of helium-4 gas was found in the air of the chamber. The experimenters cited this evidence in support of their conclusion that fusion had been achieved.
Which one of the following, if tree, would cast doubt on the experimenters’ conclusion

A．Helium 4 was not the only gas found in the experiment chamber.

B．When fusion is achieved, it normally produces several byproducts, including tritium and gamma rays.

C．The amount of helium 4 found in the chamber’s air did not exceed the amount of helium 4 that is found in ordinary air.

D．Helium 4 gas rapidly breaks down, forming ordinary helium gas after a few hours.

E．(E) Nuclear fusion reactions are characterized by the release of large amounts of heat.
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