it's about half an hour walk from here 这句话中walk 为什么要是不及物动词呢?

问题描述:

it's about half an hour walk from here 这句话中walk 为什么要是不及物动词呢?
是不是错了啊?着急

walk 既是动词 又是名词.这里是名词.
it's about half an hour‘s walk from here