Daim ntawv thov

Nws yog dav siv nyob rau hauv high kub daim ntaub ntawv, kho mob, tsev cov ntaub ntawv, chemistry, zaub mov kev lag luam, ua liaj ua teb, nkoj Chemistry.
Nws kuj tseem siv tau rau cov khoom noj, ntim dej haus, khoom siv hauv chav ua noj, tsheb ciav hlau, dav hlau, conveyor siv, tsheb, bolts, ceev, springs, thiab screen.