Kos Npe 1.11.2. Txaus ntshai lem (sab laug)
Kev sib puag ncig ntawm txoj kev nrog lub vojvoog me me lossis muaj kev pom tsawg.
Ua ntsia hauv n. n. rau 50-100 m, sab nraud n. p. - rau 150-300 m, lub cim yuav tuaj yeem teeb tsa ntawm qhov sib txawv, tab sis qhov kev deb tau raws li tau teev tseg hauv Table 8.1.1 "Qhov nrug ntawm cov khoom".
Nta:
Qhov sib txawv hauv kev taw qhia ntawm lem (sab xis, sab laug). Daim phiajcim tsuas qhia txog cov kev taw qhia ntawm thawj tig tom qab lub paib.
