1, water should not be more than one-half of the capacity, you can pour directly into the green beans

2, large fire boil on the gas immediately after the change to a small fire, as long as you keep the safety valve at the little bit of gas in the bubble can be, the length of time to cook with the safety has no relationship, the general on the gas off the fire after ten minutes can be, cook for fifteen minutes on the very rotten very rotten! The time of cooking has nothing to do with safety.

3, in addition to open the lid is the same as cooking other things, to wait for the pot to cool down after the pot is not under pressure to open, but also can not be under pressure to take the safety valve to force the pressure, otherwise, the green bean soup in the pressure from the pressure valve under the action of the jet, it will be scalded.