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问题 选择题

____________ a book, and ____________ are bags.[ ]

A. This is; that

B. This is; those

C. This; that

D. These are; those

答案

答案：B

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 six bytes OSI layer 2 address which is burned into every networking device that provides its unique identity for point to point communication.
(67) is a professional organization of individuals in multiple professions which focuses on effort on lower-layer protocols.
(68) functions with two layers of protocols. It can connect networks of different speeds and can be adapted to an environment as it expands.
(69) is the popular LAN developed under the direction of the IEEE 802.5.
(70) is the popular backbone technology for transmitting information at high speed with a high level of fault tolerance which is developed under the direction of ANSI.

A．The MAC address

B．The IP address

C．The subnet address

D．The virtual address
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填空题 案例分析题

“蝴蝶泉头蝴蝶树，蝴蝶飞来千万数。首尾连接数公尺，自树下垂疑花序。”每年的4、5月间，大理蝴蝶泉一带有数量庞大的大丽王蝴蝶种群，它们的翅色有黄翅黑斑和橙黄黑斑两种。研究得知，黄翅黑斑（A）对橙黄黑斑（a）是显性，且亲代基因型及比例是AA（30%）、Aa（60%）、aa（10%）。若它们随机交配，请据孟德尔的分离定律计算，并回答问题：

近年发现该种群出现了突变的白翅蝶，专家分析该种群的基因频率将会发生改变。请分析白翅基因的频率可能会怎样变化（）
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