倾斜井巷更换和翻修轨道时,开工前上部挡车器或挡车栏必须处于()状况,方可进入现场施工。
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Electronic goods such as laser prints and computers all contribute to_________
A teacher who is 74 will be able to make his lessons more lively.
You can save a lot of time and avoid misunderstandings if you communicate clearly and ____________.
All the flights having been canceled because of the snowstorm, many passengers_________(除了乘火车外什么都不能做)