（）保护只能作为变压器的后备保护。A、瓦斯 B、过电流 C、差动 D、过负载 发布时间：2021-04-11 15:08 │ 来源：www.tikuol.com 题型：单项选择题 问题： （）保护只能作为变压器的后备保护。A、瓦斯B、过电流C、差动D、过负载
题型：单项选择题 选择框格内单词的适当形式填空，每词限用一次。shop, make, throw, how, it, many, give, had, care, use Dear Sir, I would like to make a comment on the plastic bags which we use in our daily life. I thought that the 1 effect (影响) from all these bags on our environment was well -known and that most people know they should not keep 2 them but collect them in the dustbin ( 垃圾箱). However, one of the 3 near my home seems to use 4 of these bags than ever before. Red ones, white ones and blue ones-it 5 no difference. They don't 6 about the problems of environment. They still use plastic bags to wrap (包装) most of the things every day. When I went shopping the other day, I bought two things, and I 7 three bags to wrap 8 . Is it necessary 9 so many bags? Everyone should realize 10 important it is to clean our environment. Yours sincerely, Tony Wang 查看答案
题型：单项选择题 建筑工程施工安全技术下列安全防护装置中，主要用于高架升降机，为防止吊笼下行时不停机，压迫缓冲装置造成事故的安全防护装置是( )。A．上料口防护棚B．超载限位装置C．下极限位装置D．通信装置 查看答案
