go out on a limb 担风险；冒险

【例句】
I'm gonna go out on a limb here.
我要来担担风险了。

I'll go out on a limb and predict that 75% of today's venture capital firms will not exist five years from now.
我要大胆预测一下，五年后75%的风险投资公司将不复存在。