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问题 单项选择题

血钙降低常见于

A．原发性甲亢
B．佝偻病
C．维生素D摄入过多
D．急性肾衰
E．恶性肿瘤骨转移

答案

参考答案：B

解析：佝偻病是婴幼儿时期常见的慢性营养缺乏性疾病。因缺乏维生素D，钙吸收不良，导致血清钙离子浓度降低所致。

单项选择题

一般认为，现代意义上的经济法学的发祥地是( )

A．美国

B．法国

C．德国

D．英国
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单项选择题

For each blank, choose the best answer from the four choices and write down on the answer sheet.

(66) is a one-way function that takes an arbitrarily long piece of plaintext and from it computes a fixed-length bit string.

(67) is a protocol that most USENET machines now use it to allow news articles to propagate from one machine to another over a reliable connection.

(68) is an approach preferred by cable TV providers. In this solution the fiber terminates at an optoelectrical converter and the final segment is a shared coaxial cable.

(69) is a device used to connect two separate network that use different communication protocol.

(70) is a digital-to-digital polar encoding method in which the signal level is always either positive or negative.

66（）

A．MD

B．RSA

C．DES

D．MIB
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