英文關鍵字
chemistry
research
oxygen
line
symbol
o2
diatomic
molecule
bubbles
facial
medical
equipment
linear
background
lined
online
tool
tree
plant
laboratory
lungs
tank
burning
fire
saturation
chamber
clouds
electronic
device
gadget
breathe
atmosphere
health
icon
motion
graphic
animation
pictogram
hd
animated
item
sign
color