hill
加入词篮hillside
valley
canyon
steep
ridge
mount
outback
flat
low
lake
pond
pool
stream
river
fill
Arctic
altitude
level
rock
tough
hard
fossil
iceberg
earthquake
map
chart
spring
well
spring
universe
planet
Jupiter
earth
Mars
star
galaxy
satellite
rocket
moon
moonlight
sun
space
spacecraft
spaceship
space station
astronaut
Cancer
orbit
chemistry
metal
thin
thinner
air
sky
physics
physical
science
scientific
scientist
experiment
electronic
energy
matter
material
heat
move
movement
moving
mobile
roll
turn
still
yet
already
however
although
though
vapour
slow
slowly
spring
light
wave
period
conductor
keep
stay
rare
energy
environment
environmental
protect
pollute
pollution
recycle
