Question

The doctor did what he could ____ the dying man .

A. save B. to save C. saved D. saving
为什么选B，请详解，谢谢。

Answer 1

The doctor did what he could ____ the dying man
.A. save B. to save C. saved D. saving
为什么选B，请详解，谢谢。
因为
The doctor did what he could to save the dying man =The doctor did what he could do to save the dying man
因为句中有do，为了避免重复，所以，省略了do。

Answer 2

你就这么理解吧 to save 意思是 为了拯救 to有的时候跟动词搭配有 为了。。。。的意思

Answer 3

to save = in order to save,