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问题 单项选择题

能自发地发生核衰变转变成另一种核素的核素称为（）

A.稳定核素

B.发生器

C.母核

D.子核

E.放射性核素

答案

参考答案：E

解析：放射性核素能自发地发生核衰变转变成另一种核素。

填空题



After its (1) to the (2) in 2001, China has taken steps towards opening up its (3) . As a condition for joining the WTO, China (4) itself to a (5) of trade liberalization, including the reduction of tariffs on cars and agricultural products. These tariffs reductions are both (6) and there is (7) for China to (8) at a faster pace.
A (9) of (10) and a more rapid and profound reduction of import tariffs would (11) of those Chinese consumers who would (12) imported products at lower prices. Second, a higher (13) into China would take away much upward pressure on the Renminbi and provide a true and lasting (14) to solving current global (15) . Indeed, even a modest (16) in the opening-up process would go a long way towards solving the problem.
The opening up of China’s markets to international competition should (17) deep reforms. Banks should be recapitalized, bad loans provisioned fully and state-owned companies’ runaway indebtedness (18) . Only when real progress in these areas is made should China begin to consider a reform to its (19) . Doing it any earlier would be highly (20) .
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单项选择题 共用题干题

患者男，65岁，消瘦、乏力半年，实验室检查未见异常。超声示腹部包块，其内回声不均匀。

为明确病变起源于腹膜腔还是腹膜后，首选的检查方法为（）

A.多普勒

B.MRI

C.CT平扫及增强

D.消化道钡餐造影

E.腹部平片
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