ring once短语⁹⁶⁶⁷⁷⁺⁶ 基本例句 🌏响铃一次；只响一次；铃声只一次 A bell will ring once2 minutes before reaching the time limit of a presentation. The presenter should conclude the presentation within the remaining2 minutes. 当发表论文的时限尚馀2分钟时，大会工作人员会呜铃一下，以示发言者应于所馀2分钟内完结其讲话。 www.21pa.org.mo