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大千世界形形色色的物质最基本成分--元素组成的．根据所学“元素”知识回答下列问题： （1）一种元素与另一种元素的根本区别是______数不同．元素的化学性质与原子______关系密切． （2）地壳中含量第二的非金属元素是______（填“元素名称”）；地壳中含量第二的金属元素是______（填“元素符号”）． （3）食盐水中所含元素有______（用元素符号表示）． （4）为理解物质、元素、原子之间的关系进行了下面类比：将蔬菜看物质，那么芹菜、白菜、菠菜等组成元素，而一颗白菜可以看成一个原子．请模仿的叙述，写出一例类比物质、元素、原子关系的比喻______．
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【单选题】Actually, over 60 percents of the world s 580 million older people live in developing countries. An increasing number of people in these lands are reaching old age【C1】______better health care and impr...
A.
as usual as
B.
as a result of
C.
as a rule for
D.
as a matter of
【单选题】According to the passage, what truely results in the impoverishment of the developing countries?
A.
The rapid growth of population.
B.
The presenvation of rainforests.
C.
The cutting of rainforests.
D.
The conflicts between developed countries and developing countries.
【单选题】The universities administrators most probably agree that the rankings should ______.
A.
count completely on peer evaluations
B.
count out the rates of alumni giving
C.
be done by a more convincing magazine
D.
be based on date supplied by the presidents
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