【单选题】The fuel booster pump and steam to fuel heater, together with fuel pipe heater tracer line should be shut off as soon as the ____ order is acknowledged.
【简答题】The heaters are arranged in series and the liquid condensate collected in the steam trap of one heater is flashed to the pressure of the preceding heater. 这个句子的结构是怎样的?这个句子的几个主要的成分分别是哪些?将后置定语部分翻译成中文?