英文關鍵字
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animation
arsenic
atom
atomic
background
blackboard
bond
calcium
carbon
chalkboard
chemical
chemistry
cobalt
copper
doodle
education
electron
element
formula
gas
gold
greenboard
halogens
handwriting
helium
hidef
hydrogen
icon
iron
lab
laboratory
lead
material
mercury
metal
micro
microscopic
mineral
molecular
molecule
nickel
nitrogen
nonmetals
oxygen
periodic
physics
platinum
potassium
presentation
research
school
science
scientific
sign
silhouette
silver
sodium
study
substance
sulfur
symbol
table
teaching
theory
titanium
tutor
university
uranium
writing
zinc