Thaum twg yog lub chaw thau khoom xav tau?

Thaum twg yog lub chaw thau khoom xav tau?

1) Hauv cov pa hluav taws xob tsawg, cov kua yuav ua kom khov kho los ntawm cov raj dej ntws los ntawm cov raj dej ntws los ntawm cov raj hluav taws xob tsis pub dhau qhov yuav tsum muaj kub thiab txias {}}

2) Cov kua dej siab tshaj plaws muaj kua hluav taws xob tsis zoo ntawm qhov ntsuas hluav taws xob tsis zoo tuaj yeem muab kev thauj khoom kom tsim nyog rau lawv, kom muaj kev thauj mus los du {}

3) rau kev ua kom yooj yim xws li roj crude, roj hnyav, yog tias cov kav dej, yog tias cov roj av yuav tsum tau siv .

Nws yog qhov tseem ceeb siv hauv kev thauj khoom ntawm cov khoom siv ua kua hauv cov khoom lag luam petrochemical siv cov khoom siv roj ntsha thiab muaj ntau yam kev nyab xeeb thiab hloov kho kom ruaj khov thiab hloov pauv thiab hloov pauv}