every morning Mr.Smith takes a to his office A.20 minutes' walk B.20-minute walk

问题描述:

every morning Mr.Smith takes a to his office A.20 minutes' walk B.20-minute walk
同上 我觉得答案是B ,不过我记得这题以前做过,应该是B啊.

选B
a 20-minute walk 就是冠词+形容词+名词 构成
20-minute 在这里是变形的形容词用法 就相当于 a 2-year-old boy
希望这样能让你理解我也觉得