PRD可更换式电涌保护器中新增加Uc值为“440/440”在选用时与原先_爱下问搜题

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问题问答题简答题

PRD可更换式电涌保护器中新增加Uc值为“440/440”在选用时与原先的“440/275”有何区别？

答案

参考答案：

Uc值为‘440/440’的产品提升了L/N的最大持续工作电压，其主要应用在电网电压波动较大，如郊区等；以及在用户对L/N的最大持续工作电压要求较高的场所。

完形填空

Mr. Smith lived in a village far away __ 16_ a town . One day he felt very ill and every one 17 he would die . They sent for a doctor . The doctor 18 and looked at the man closely . The doctor asked for a pen and ___19 paper to write down the name of the medicine(药). But there was no pen _20 _ paper because all the villagers never went to school before. The doctor had to use a piece of charcoal to write down the name of the medicine on the door of the house. “Get this medicine for him .” he said , “and he will ___ 21 _ get better .” Mr Smith’s family and friends didn't know _ _22__ to do . They could not read the __ 23_ writing . Then Mr. Smith’s son had an idea . He shut ___24 the door of the house , put it on his back and ran to the nearest town . He bought the medicine , he soon got rid of his __ 25 . He would not let anyone wash the magic words from the door .

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