Charles did what he could ---the servant ,although he himself was in danger.A rescueB.to rescue请问为什么选A情态动词后不应该加动词原形吗?

Charles did what he could ---the servant ,although he himself was in danger.A rescueB.to rescue请问为什么选A情态动词后不应该加动词原形吗?
Charles did what he could ---the servant ,although he himself was in danger.A rescueB.to rescue
请问为什么选A情态动词后不应该加动词原形吗?

Charles did what he could ---the servant ,although he himself was in danger.A rescueB.to rescue请问为什么选A情态动词后不应该加动词原形吗?
同学,很高兴回答你的问题
才看到你发来的求助题,所以回答晚了些
正确答案：选【B】
即：Charles did what he could to rescue the servant,although he himself was in danger.
翻译：查理斯尽他所能来救这个仆人,尽管他自己的处境也很危险.
解析：是的,我们都知道情态动词后面加动词原形,但是本句中what引导的宾语从句中的could后面省略了动词do,而to rescue 是动词不定式作目的状语,即
Charles did what he could do to rescue the servant,although he himself was in danger.
只不过是这个do省略了,为了避免重复.
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这是一个固定句型，意思是 尽某人全力做某事：
do what one could to do sth

这句话的意思是charles尽了全力（did what he could），去救（to rescue）....尽管...
楼主重新领会一下句子结构吧