English is not my main language, but I'm pretty sure I have a rock solid foundation since I learned it in high school.
If I recall and memory serves, one cannot use past tense verbs twice in the same sentence, for example:
Why didn't you came last night?
This is completely wrong (I do not remember why, I just know it is) and it should be changed to this:
Why didn't you come last night?
That would make it valid.
I have this other sentence:
"well you did this to me, and that's why I did that."
Does the same "rule" apply to the above sentence?