英文關鍵字
algae
biology
ecology
ecosystem
environment
floating
green
lake
leaf
natural
nature
plant
polluted
pollution
pond
river
seaweed
summer
water
英文關鍵字
algae
biology
ecology
ecosystem
environment
floating
green
lake
leaf
natural
nature
plant
polluted
pollution
pond
river
seaweed
summer
water