英文關鍵字
african
animal
animals
aquatic
behavior
biodiversity
close
conservation
ecosystem
environment
fauna
greens
habitat
hippopotamus
hippopotamuses
jaws
large
mammal
mouth
natural
nature
open
outdoors
pair
pool
predator
river
roar
rocks
splash
stream
sunlight
swimming
teeth
tusks
vegetation
video
water
waterfall
wet
wild
wildlife
zoology