指弱者处在非常危险的情况下，后果很严重to be in a perilous situation; a lamb in a tiger's mouth

• 在目前中国A股的糟糕环境下，养老金入市完全是羊入虎口。

  In the current desperate environment for China's A-Shares, pensions joining the market are in a perilous position.

• 周某嫁给男友，无疑是羊入虎口。

  For Zhou to marry her boyfriend is undoubtedly a dangerous thing to do.