句子could you asked sb.to do sth.中为什么could 后面ask是过去时,could后面动词

could not but后面是do还是to do来着 一个英语问题teach sb to do sth如果句子是过去时,teach要改成过去式,后面的 动词（do） 要不要也 would you mind、could you please后面是加to do 还是doing? Do you know whether I could pass the exam? 为什么whether后面用的是co could you please do sth后面可以用not at all回答么 为什么这个句子情态动词后面可以用不定式?The doctor did what he could to save the 宾语从句中Could引导的疑问句后面动词原型例如Could you tell me if they can get th Could/Would you please do sth?could would 是什么词性? Could you tell me-----后面接宾语从句时,宾语从句是否用过去时? Could you tell me 后面句子的语序 I wish I could be like you.could后面为什么要加be? 为什么ask sb to do sth的否定形式是ask sb not to do sth