请教一道高一填空题,在线等

题目

请教一道高一填空题,在线等
---We would have walked to the station, it was so near.
---Yes. A taxi _____（not be）at all necessary.
答案应该是wasn't 还是hadn't been呢?理由是什么?

答案

We could have walked to the station,it was so near.
Yes.A taxi ________ at all necessary.
选.hadn’t been
We could have walked to the station,it was so near是虚拟语气,其实他们已经乘过轿车了,过去的过去用过去完成时