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《自然》杂志曾报道我国科学家通过测量SiO 2 中 26 Al和 10 Be两种元素的比例确定“北京人”年龄的研究结果,这种测量方法叫“铝铍测年法” 。完成下列填空: (l) l0 Be 和 9 Be _______ 。 a. 是同一种原子 b. 具有相同的中子数 d. 具有相同的化学性质 d.互为同位素 (2) 写出A1与NaOH溶液反应的化学方程式: ___________________________ 。 (3) 研究表明 28 A1可以衰变为 26 Mg,可以比较这两种元素金属性强弱的方法是 __________ 。 a. 比较Mg (OH) 2 与A1 (OH) 3 的碱性强弱 b. 在氯化铝和氯化镁的溶液中分别滴加过量的氢氧化钠溶液 c. 将打磨过的镁带和铝片分别和热水作用,并滴入酚酞溶液 d. 比较这两种元素的单质的硬度和熔点 (4) 目前还有一种测量方法叫“钾氩测年法”。写出和Ar核外电子排布相同的两种阴离子的半径由大到小的顺序: _______ ( 用化学符号表示);其中一种离子与钾同周期相邻元素的离子所形成的化合物可用作干燥剂,用电子式表示该物质的形成过程 __________ 。
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B.
IP地址是由IP协议规定的，包含有网络号与主机号两个部分
C.
主机地址全为“1”的IP地址称为网络地址
D.
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【简答题】translation practice: 1. Cigarettes were the death of me. ( 静 态→ 动 态 ) 2. If the man who was seen to take an umbrella from the City Church last Sunday evening does not wish to get into trouble, he w...
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相关题目：
【单选题】下列关于TCP/IP协议及IP地址的叙述错误的是______。
A.
TCP/IP协议既支持面向连接的服务，也支持无连接的服务
B.
IP地址是由IP协议规定的，包含有网络号与主机号两个部分
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【简答题】Grandmother: John, I've got a stomach ache ____1___ won't go away. Where did you buy those vegetables? John: I got them from the stall (摊位) ___2____ is on the corner. Gra...
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A.
In New York City.
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D.
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A.
２１℃以下
B.
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C.
７０℃以上
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【单选题】听力原文：W: Excuse me, where did you get to know about the new product? M: From your advertisement on TV. Q: Where did the man get to know about the product? (9)
A.
On television.
B.
In the newspaper.
C.
On the Internet.
D.
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【简答题】translation practice: 1. Cigarettes were the death of me. ( 静 态→ 动 态 ) 2. If the man who was seen to take an umbrella from the City Church last Sunday evening does not wish to get into trouble, he w...
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【简答题】Now that you are in for it, you must carry on. 2. Cigarettes were the death of me. 3. If the man who was seen to take an umbrella from the City Church last Sunday evening does not wish to get into tro...
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