Cov yam ntxwv thiab cov yam ntxwv: Tsis muaj kev mos thaum kub siab lossis tawg thaum txias heev; tuaj yeem tsim nrog ob txheej qauv rau kev rwb thaiv tsev zoo dua, ua rau nws tsim nyog rau kev tsim khoom thaum lub caij ntuj no hauv cov liaj teb hauv thaj chaw txias heev ntawm sab qaum teb; muaj zog tiv taus kev tawg thiab kev cuam tshuam, muaj peev xwm tiv taus kev cuam tshuam ntawm cua, daus, thiab nag xob nag cua; tus phooj ywg ib puag ncig, huv si, yooj yim ntxuav, thiab tsis tas yuav saib xyuas tshwj xeeb. Cov khoom no feem ntau yog siv rau hauv cov teb xws li zaub mov, dej haus, tshuaj, optics, khoom siv hluav taws xob, kho vajtse, khoom ua si, thiab tshuaj pleev ib ce.
