hang in the balance
have reached a critical point；have two equally possible results到了关键时刻；安危（胜负、成败）未定She is very sick and her life hangs in the balance．她病得很厉害，生死难卜。
The future of the nation was in the balance．国家的存亡处于紧急关头。
The outcome of the game hung in the balance．比赛的结果胜负难分。