英文關鍵字
altruism
bag
blue
bottle
care
clean
cleanup
collecting
collection
concept
cup
dirty
earth
eco
ecological
ecology
ecosystem
environmental
forest
free
friendly
garbage
girl
glove
green
hand
human
natural
nature
off
out
outdoor
packet
park
plastic
pollution
preservation
problem
take
takes
trash
volunteer
volunteering
work