—______do you write to your parents?

-- Twice a month.

A．How often

B．How many

C．How long

D．How soon

根据《煤矿重大安全隐患认定办法（试行）》之规定：煤与瓦斯突出矿井未按规定配备防治突出装备和仪器的，不属于煤矿重大安全生产隐患。