Ua ntej, pw thiab lem sab laug thiab sab xis. Yog hais tias lub caij nplooj ntoo hlav tsis txav los yog tsis sib xws, thiab nws tuaj yeem rov qab tau rau nws lub xeev tam sim ntawd, nws qhia tau tias cov fording zoo yog tsim nyog.
Thib ob, siv ob txhais tes co lub taub ntim rov qab thiab tawm. Yog tias nws yog qhov ruaj, nws cov ncej zoo dua.
Thib peb, thaum mus yuav tawv tawv quav, koj tuaj yeem siv koj cov ntsis ntiv tes los tuav ib qho chaw thiab rub nws mus rau sab saud. Yog tias koj xav tias muaj zog thiab rov zoo lawm, nws txhais tau tias qhov zoo tau zoo heev.
Thib plaub, qhov siab -}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}}} fining hauv nws cov npoo av, thiab cov ntaub npuag yog mos thiab tawv.
Thib tsib, rau lub txaj folding nrog hlau ncej qauv, nws yog ib qho tsim nyog los them sai sai thiab tsis muaj txheej thiab cov txheej thiab muag muag. Yog tias cov xim ci keeb yog saws, saum npoo ntawm cov yeeb nkab steel yog yooj yim los ua cov khawb, oxidation thiab xeb, thiab tsis muaj lus dev.
