A.spheroid B.loxodrome C.carene D.sphere
A.incoming data B.working data C.outgoing data D.new data
A.Filter masks with a combination filter should be brought and used whenever necessary B.Only explosion-proof equipment(marked EEx)should be used C.Avoid breathing petroleum gases,especially if they come from sour crude(smell of rotten eggs) D.so far as possible,take early and substantial action to keep well clear