it happend once in the blue moon根据这句话“不可能”编对话
问题描述：
it happend once in the blue moon
根据这句话“不可能”编对话
答
It is impossible to happen in the blue moon.
是这个意思吗？
答
A. I have seen a pink dog before.
B. Yes, it happened once in the blue moon.
A. Do you know that cows eat meat?
B. Yes, it happened once in the blue moon.
...
答
千载难逢应该是once in a blue moon