填空题 If the power frequency is weaker than the frequency generated by the Earth, it will not have any influence on us.

  • 1、
【正确答案】 1、N    
【答案解析】参看第一段最后一句话“ELF (Extremely Low Frequency) eletromagnic fields vibrating from 0.5 to 100Hz，even if they are weaker than the Earth's field，interfere with the cues that keep our biological cycles properly timed”．