请问第三人称过去式是用did还是用does?1.She does not konw London very well 2.He did nor understan2.He did not understand English请问这两句话都是过去式 为什么一个用does 一个用did?可以互换吗?

问题描述:

请问第三人称过去式是用did还是用does?
1.She does not konw London very well 2.He did nor understan
2.He did not understand English
请问这两句话都是过去式 为什么一个用does 一个用did?可以互换吗?