the fat is in the fire (idiom)
1.生米已成熟飯
Sorry, dear. The fat’s in the fire. No way can you retract the “of-fer” without doing a lot of damage to the relationship.
對不起，親愛的讀者，生米已成熟飯，妳是不可能在不傷及雙方感情的情況下取消答應人家的事。
2.事情大了
I wish you had written to me before you drew the battle lines with your daughter. Now, however, the fat is in the fire, and you must deal with it.
妳應該在跟女兒鬥氣之前寫信給我，不過，現在事情大了，妳非自己去處理不可。
