题干

W、X、Y、Z是四种常见的短周期元素,其原子半径随原子序数变化如图所示。

已知W的一种核素的质量数为18,中子数为10;X和Ne原子的核外电子数相差1;Y的单质是一种常见的半导体材料;Z的非金属性在同周期元素中最强。下列说法不正确的是(  )

A:对应简单离子半径:X<W

B:对应简单气态氢化物的稳定性:Y<Z

C:与Z元素同主族的元素最高价态均为+7

D:Y的氧化物能与X的最高价氧化物对应的水化物反应

上一题 下一题 0.0难度 选择题 更新时间:2019-10-09 09:46:07

答案(点此获取答案解析)

C

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    If you have ever been left wondering why your emails are riddled(充斥着) with grammatical errors, or why you can never quite find the right phrase, it may be because you are typing with both hands.

    Our vocabulary becomes richer and our writing style becomes more fluent when we type using just one hand, scientists have found. "Typing can be too fluent or too fast, and it can actually weaken the writing process," said Srdan Medimorec, the lead author of the study conducted at the department of psychology at the University of Waterloo, Canada. "It seems that what we write is a product of the interaction(互动) between our thoughts and the tools we use to express them."

    Using text-analysis software, researchers asked 103 university students to write essays under different conditions, using one hand to type and using both hands to type. The software was used to analyze(分析) elements of the essays, such as range of vocabulary, sentence complexity and the cohesion(衔接) of the writing.

    Researchers found that participants' vocabulary became more advanced when they typed with one hand rather than two. The research team said that by slowing our writing down, typing one-handed allows more time for an internal (内在的) word search, resulting in a larger variety of words.

    In contrast, fast typists might just write the first word that comes to mind. However, it is important not to slow typing down too much. Those who typed essays one-handed in the current study slowed down to about the speed of handwriting.

    This is the first study to show that changing people's typing can make their writing get better. The researchers suggested that the speed of writing could affect writing quality regardless of the tools used, whether they are computers, or pen and paper, although further research would be required to prove that idea.