英文關鍵字
air
anchored
balloon
buoyant
burners
burst
coil
double
envelope
equipment
fabric
flames
flight
frame
gas
heat
jet
metallic
mouth
nylon
propane
regulators
ropes
transportation
upward
valve
英文關鍵字
air
anchored
balloon
buoyant
burners
burst
coil
double
envelope
equipment
fabric
flames
flight
frame
gas
heat
jet
metallic
mouth
nylon
propane
regulators
ropes
transportation
upward
valve