Feem ntau tuaj pwm tsim ntawm ob yam ntawm qhov:
Ib hom yog cov txheej txheem ntu, uas koom nrog ncaj qha rau qhov ua tiav ntawm qhov txheej txheem thiab muaj qhov sib chwv ncaj qha nrog rau seem, suav nrog cov chaw ua haujlwm, qhov chaw muab tso, tsis xa khoom thiab nias ntu, thiab lwm yam.;
Ib hom yog cov ntu. Hom seem no tsis ncaj qha rau hauv kev ua tiav tiav, tsis pub nws tsis cuam tshuam ncaj qha nrog cov seem. Nws tsuas yog ua kom tiav ntawm kev tsim cov txheej txheem pwm, lossis txhim kho kev ua haujlwm ntawm pwm, nrog rau cov coj kev coj ua thiab ntu ua haujlwm. , Cov khoom txheem thiab lwm qhov chaw, thiab lwm yam, raws li qhia hauv Table 1.1.3. Nws yuav tsum tau taw qhia tias tsis yog txhua txhua tus neeg tuag yuav tsum muaj 6 ntu saum toj saud, tshwj xeeb yog cov txheej txheem ib leeg tuag, tab sis cov seem ua haujlwm thiab cov ntu tsim nyog yog qhov tseem ceeb.
