句子中在could/can/shall/should/may/might/will/would后面的动词都是原型吗

句子中在could/can/shall/should/may/might/will/would后面的动词都是原型吗 在问句中,句子的首单词,在什么情况下分别用到can/could/will/would/are/do/did/shall?它们之间有何区别本人对这个问题一直感到很迷糊, 在时态为过去式的句子中can需要变为could吗?如题 shall是用在将来时的句子中吗? should,must,can,may,shall,could,might的用法 Will would; shall should ;can could区别和用法 will would ; shall should ; can could ; must need ; may might以上每组有什么区别,分别应用在什么时候? can could 在疑问句中有什么区别? 在一般进行时的句子里用情态动词can 还是用could?could只有在过去式时用吗? shall,must,will,would,can,could,委婉程度怎么样,是不是用can最委婉,那shall呢 who can tell me what is the different between shall/should can/could?xD 例句：l could speak English.在疑问句中could可以代替can,在陈诉句中可不可以? could是不是can的过去式、?它是不是不能在将来时的句子出现、? have had can could may maight did在句子中的用法 shall在英语中是什么意思? shall we能用在句子后面吗? be,have,do,shall,will,should,would 各自在句子中用处`初中版, I can(not) imagine that they could (not) finish it in such a short time上面句子中的not 应该放在can后面还是could后面为什么?