金垂亡之际，南宋尚不知唇亡齿寒，大祸将至，竟作出联蒙灭金的决策，结果寸土未得，实力暴露，最终走向灭亡。
Worse still , when the Jin was doomed , the Southern Song even made a decision to join with the Mongols to resist the Jin ， not knowing that it would soon follow the Jin 's fate .
联蒙灭金