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问题 单项选择题

为适应扩大对外开放和引进先进技术的需要，可将( )增加为鼓励类条目。

A．国内急需发展的产业和产品
B．国外急需发展的产业和产品
C．国内发展的产业和产品
D．国外发展的产业和产品

答案

参考答案：A

问答题 论述题

简述《诗经》对后代文学的影响。
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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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