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问题 不定项选择

原子核A 经β衰变（一次）变成原子核B ，原子核B 再经α衰变（一次）变成原子核C ，则下列说法中正确的是[ ]

A．核A 的中子数减核C的中子数等于2

B．核A 的质子数减核C 的质子数等于5

C．原子核A 的中性原子中的电子数比原子核B 的中性原子中的电子数少1

D．核C 的质子数比核A 的质子数少1

答案

CD

单项选择题

D


Any mistake made in the printing of a stamp raises its value. A mistake on one inexpensive postage stamp has made the stamp worth a million and a half times its original (本来的) value. The mistake was made more than a hundred years ago in the British colony (殖民地)of Mauritius, a small island in the Indian Ocean. In 1847 an order for stamps was sent to a London printer—Mauritius was to become the fourth country in the world to issue (发行) stamps.
Before the order was delivered(传达), a party was planned at Mauritius’Government House, and stamps were needed to send out the invitations. A local printer was told to copy the design for the stamps. He printed the words " Post Office " instead of " Post Paid " by mistake on the several hundred stamps that he printed.
Today there are only twenty-six of these misprinted stamps left—fourteen Onepenny Orangereds and twelve Twopenny Blues. Because of the Twopenny Blue’s rareness (稀少) and age, collectors have paid as much as $ 16800 for it.

The mistakes on the locally printed postage stamps was in the ______.

A．size

B．words

C．price

D．colour
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单项选择题

按照每（）家营业网点配备1名专职会计检查辅导员的比例配备。

A.5

B.10

C.15

D.20
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