题干

下列说法符合安全用电原则的是(   )

A:家用电器失火时,先灭火,后切断电源

B:用湿布擦拭工作中的电器

C:更换灯泡前应断开电源开关

D:电灯开关可以接在火线上,也可以接在零线上

上一题 下一题 0.0难度 选择题 更新时间:2019-07-14 09:45:44

答案(点此获取答案解析)

C

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          Based on new analysis, we are rapidly approaching major climate change and the effects on society and the environment could be quite severe. Geographers predict that within the next eighty years, current world climate zones could shift and some could completely disappear. Polar regions will get colder while tropical regions will get even hotter, forcing animals to migrate (迁徙) north.

         Climate changes like these could lead to the spread of diseases. Tropical storms and hurricanes will not only increase but may also become more intense. If the changes come too quickly, animal and plant species may not be able to adapt fast enough and could disappear.

         According to Science Daily, a new study predicts that by the year 2100, many of today's familiar climates will be replaced by climates unknown in today's world. It is urgent that we reduce the risks of these far­reaching consequences for the whole world. The planet itself has been showing signs of change. In 2004, a serious tsunami created by a major earthquake killed thousands in Sumatra and in 2008, thousands died in China because of another severe earthquake. Egypt was hit in 2009 with a major earthquake and Haiti was devastated in 2010 by yet another massive earthquake.

         Within just the last few months, new reports from around the world have been coming in and most agree that our climate situation is much worse than previously thought. At this point, it doesn't matter what is causing it, but rather, what can be done about it. What's more, our world is getting more and more unstable every year. There is war and threat of war everywhere. Natural disasters are becoming more frequent and serious.

         However, other planets are experiencing global warming as well as our own and some scientists believe there may be some connection between this. No one knows anything for sure at this point because there is simply not enough data.