问一个英语知识在否定句或者一般疑问句中,现在进行时和过去式要不要还原?have to后面是不是要加动词原形？

我所说的还原不是这个意思。 应该是： She is reading a story book. She isn't （reading） a story book. Tom listened to CDs yesterday Tom didn't listen to CDs yesterday 改一般疑问句 Gina is writing a letter to her pen pal Is Gina （ writing ）a letter to her pen pal? 即：进行时态仍然用doing,但过去式要改成原型。 请注意上面句子括号内部分。