Kev txiav iav 1. Nws yog ib qho tsim nyog kom paub meej tias cov iav yuav raug txiav yog deformed los yog tawg, thiab nws yuav siv tsis tau yog tias nws tsis tsim nyog. 2. Lub iav raj ( pas nrig) ​​yuav tsum tau passivated ua ntej yog tias ob qhov kawg yog ntse. 3. Ua ntej siv lub trowel los kos ib qho kos ntawm qhov chaw