问题 选择题
下列所给粒子间的数量满足2:1关系的是(  )

A.氧化钠中的氧离子和钠离子

B.二氧化硅中的硅原子和氧原子

C.过氧化钠中的钠离子和过氧根离子

D.碳酸溶液中的氢离子和碳酸根离子

答案

答案:C

选择题
写作题

任务写作。

阅读下面的短文,然后按照要求写一篇150字左右的英语短文。

     The southwest of Australia has been named as one of 25 "hot spots" for future species extinction because

of global warming. A new study says global warming will become a top cause of extinction across the world,

with thousands of species of plants and animals likely to be wiped out in the coming decades.

     According to the study, global warming ranks among the most serious threats to the planet's biodiversity

and, under some conditions, may be more than that due to deforestation, this study provides even stronger

scientific evidence that global warming will result in catastrophic species losses across the planet. Last month,

a U.N. study said humans were responsible for the worst extinction and urged extra efforts to reach a U.N.

target of slowing the rate of losses by 2010.

     Scientists disagree about how far global warming is to blame compared with other human threats such as

deforestation, pollution and the introduction of some species to new habitats. But the new study looks at the

25 "hot spots"-areas that contain a big concentration of plants and animals - and predicts that 11.6 percent of

all species, with a range from 1 to 43 percent, could be driven to extinction if levels of heat trapping gases in

the atmosphere were to keep rising in the next 100 years. 

     写作内容 1. 概括短文的内容要点,该部分的词数大约为30字; 

                     2. 以“Globe Warming Threatening Our Planet”为题,谈谈全球变暖对环境的影响。

                            至少包含以下内容要点,该部分词数大约为120。

                     A. 全球变暖的主要原因;

                     B. 全球变暖的危害;

                     C. 谈谈如何解决该问题。

     写作要求:你可以使用实例或其它论述方法支持你的论点,也可以参照阅读材料的内容,但不

要抄袭阅读材料中的句子。

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