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问题 多选题

核内质子数不同、核外电子数相同的两种粒子，它们可能是（　　）

A．两种不同元素的原子

B．两种不同元素的原子和离子

C．两种不同元素的离子

D．同种元素的原子和离子

答案

A、不同元素的原子，电子数肯定不同，故A不符合条件；

B、一种元素的原子和另一种元素的离子，符合不同质子数、相同电子数的两种粒子，故B符合条件；

C、不同元素的离子，如Na+  和 Mg2+，都是离子，而且质子数不同，而电子数相同，故C符合条件；

D、同一元素，质子数就一定相同，故D不符合条件．

故选BC．

完形填空

Here in China, as the awareness of climate change improves, realizing a low-carbon way of life, also known as reducing your carbon footprint, is a growing trend among young Chinese.

Zheng Xiyu works at  小题1: office in Beijing’s Central Business District．Every day,  小题2:  takes her roughly 40 minutes to go to work by bus．But she is thinking of  小题3:  (switch) to a different way of transport--a bicycle．When buying clothes, she will choose those purely made of cotton, 小题4: it takes less carbon to produce cotton clothes．She’s also adapting to a vegetable diet as livestock(家畜) can make many contributions  小题5:   today’s most serious environmental problems.

A recent survey shows 小题6:  78% of all the 17,000 people questioned have developed environmentally friendly habits in their daily lives．They are doing things, such as taking reusable shopping bags to the store and setting the air conditioner at a temperature above 26oC in summer.

On many popular  小题7:   (society) networking websites, people are advocating a low-carbon lifestyle．Their tips include using the stairs and public transport more frequently 小题8:  elevators and cars．They hope this lifestyle  小题9:  (become) more than just a trend within certain groups.

As the most populous nation on the planet with the world’s fastest growing economy, China has become the second biggest emitter(排放者) of greenhouse gases．The recent extreme weather in the southern regions reflects a serious environmental challenge．Experts say there is no time  小题10:   (delay) with the effort to reduce carbon emissions.
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问答题 简答题

为了在10kV跌落式熔断器与10kV电缆头之间工作时，能与跌落式熔断器上桩头有电部分保持安全距离，在安装时宜采取什么措施？
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