subaqueous fan-fan deltaic depositional system
Changing flat roof to slope roof
diagonal ridge for hip roof，vertical ridge for gable roof
flat- roof-to- slope-roof
flat-roof-to-slope-roof
flat-roof-to-sloping roof
roof pressure roof weight
roof prism (=roof-angle prism)
fan marder [= fan marker beacon]
the selection of primary air fan and secondary air fan
10104 m3 floating roof tank