1.Hnub no kev txiav-ntug tsim, zoo-zoo thiab yooj yim-rau-siv tag nrho cov tsos, ua los ntawm txhim khu kev qha Cheebtsam, tag nrho cov ntaub thaiv npog yuav tiv thaiv lub counterweight system ntawm niaj hnub hnav thiab tsim kua muag.
2.Qhov kev hloov kho yooj yim tuaj yeem ua kom ntseeg tau tias cov neeg siv tuaj yeem hloov kho sai thiab ua tau zoo tshaj plaws.
3.Qhov pom kev kos npe tuaj yeem qhia qhov kev hloov kho thiab qhov chaw teeb tsa kom raug, thiab txo cov kev pheej hmoo.