某装饰工程公司承接北京市某街道的一栋12层，全现浇混凝土结构的办公楼装饰工程，现安排某安全员负责该工地的消防安全管理，并做了如下工作： （）该工程的消防安全管理工作比较到位，在施工全过程中，未发生一起火灾。 问题 电、气焊切割作业前，需办理什么证件？现场须做哪些消防准备？

Small Town. If Small Town Cablevision raises its price to $40 per month, the number of subscribers will fall to 20,000. Suppose that a price of $30 per month, there are 30,000 subscribers to cable television in Small Town. If Small Town Cablevision raises its price to $40 per month, the number of subscribers will fall to 20,000. At which of the following prices does Small Town Cablevision earn the greatest total revenue？A．either＄30or＄40permonthbecausethepriceelasticityofdemandis1．0．B．＄30permonth．C．＄40permonth．D．＄0permonth．