The air-conditioner is running in the winter and to be stopped, we should（） A: close Fan and Humidifier at the same time B: firstly close Fan and then close humidifier immediately C: firstly close humidifier and then close Fan immediately D: firstly close humidifier and then close Fan after 30 second

The humidifier's valve of air-conditioner should be____, when the temperature is 5-8℃ in the winter. A: decreased B: increased C: fixed D: closed

The opening of the humidifier’s valve of air-conditioner should be ____, when temperature is lower than 0℃. A: decreased B: increased C: fixed D: closed