20.He has many different ways ------that work.

选A. 此题主要考查way的用法, 此句中way意为"方式;方法"
在英语中,"...的方法" 有以下四种表达方式:
1. the way to do sth
2. the way of doing sth
3. the way +that引导的定语从句
4. the way + in which引导的定语从句
所以这个句子还可以写为: He has many different ways of doing that work.
相信我,没错的!就如下面的朋友讲的,此处是不定式作定语.唯一的可能是答案错了!