题干

在进行异号的两个有理数加法运算时,用到下面的一些操作:

①将绝对值较大的有理数的符号作为结果的符号并记住

②将记住的符号和绝对值的差一起作为最终的计算结果

③用较大的绝对值减去较小的绝对值

④求两个有理数的绝对值

⑤比较两个绝对值的大小

其中操作顺序正确的步骤是(  )

A:①②③④⑤

B:④⑤③②①

C:①⑤③④②

D:④⑤①③②

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答案(点此获取答案解析)

D

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    Humans and gorillas shared evolution for 23 million years. Their paths separated only six million years ago. Research on how gorillas communicate can help us understand human language development.

    Understanding how the brain works helps us see a connection between language development and non-verbal signs. These signs or movements include things like the way we move our hands or bodies or the different expressions our faces have in different social situations. A new study on gorillas showed that the right side of the body is controlled by the left part of the brain and it is also the location for language development.

    Two cameras were used to film all of one ape's movements. One of the first results was that gorillas use their right hands more when they are doing actions with their heads or mouths at the same time. This shows that there is a connection between how our brain works and the reason we use one side of our body more than the other. In addition, we can use the results of the study and our knowledge about brains to help us understand more about how language first developed in humans.

    Dr Forrester, who did the study, says the results can be useful in other ways, such as understanding language development in children. For example, some children have serious illness called “autism” which can stop them communicating normally with people. It might be possible to use the same study method to find out which children have this illness when they are very young. Doctors will then be able to start treatment early.