改错:we have studied English for about six years since I have become a middle school student.

问题描述:

改错:we have studied English for about six years since I have become a middle school student.

have become改为became很感谢,似乎有点理解了。可以讲讲since自从什么时候是要用现在完成时,什么时候后面是接过去式啊?since 后的句子过去式,since 前面是现在完成时态 since 后可以跟1过去式的句子since I was born 2 段时间加ago 比如since 3 years ago 3 点时间,比如since 2008