Question

Every morning Mr. Smith takes a ____ to his office. 为什么选D不选A/B/C

5.Every morning Mr. Smith takes a ____ to his office.

A. 20 minutes’ walk B. 20 minute’s walk

C. 20-minutes walk D. 20-minute walk

Answer 1

这个是固定句式 不能用复数 一旦用了连接符就是形容词形式了 望采纳

Answer 2

A,B所有格表示错误，C构词法错误。