英文關鍵字
attract
catching
close
drag
electromagnetic
experiment
field
focus
force
industrial
instrument
magnet
magnetic
metal
metallic
nails
objects
paper
polarity
polarize
power
pull
red
science
simple
steel
strength
tool
trick
work
英文關鍵字
attract
catching
close
drag
electromagnetic
experiment
field
focus
force
industrial
instrument
magnet
magnetic
metal
metallic
nails
objects
paper
polarity
polarize
power
pull
red
science
simple
steel
strength
tool
trick
work