the doctor did what he could to save it.为什么不是what he could do.还有to,can后能加to 请帮帮
问题描述：
the doctor did what he could to save it.为什么不是what he could do.还有to,can后能加to 请帮帮
答
医生做了他所能做的一切去救它.
TO表示目的（去救它）,直接用原型就不包含这个意思了.
可以