Why are they considered risk free?

为什么是零风险呢?

Now, these are going to be considered as risk free.

这些被视作零风险。

So you view this thing right here as risk free.

所以你可以把政府债券视为零风险。

" If we're going to be attacked, it won't be risk free."

“如果我们受到攻击，是不可能没有风险的。”

There's a 30 day money back guarantee, so it's entirely risk free.

有 30 天退款保证，因此完全无风险。