According to the original design, the plant would be able to _______ at least 8,000 pianos a year.[ ]

A. bring out

B. take out

C. put out

D. work out

排风、排烟合用管道的管径计算是按排烟量计算还是排风量计算？排烟时，排风口是不是应联锁关闭？如何联锁？是不是应有专门的风口？