Past tense short forms are a bit more tricky than present tense short forms, but not by much. First though be sure that you understand te-forms, and by extension u and ru-verbs.
Past Affirmative
Just like present affirmative was easy since it was just dictionary form. Past tense is easy too. Since you should arleady know te-forms then you know past tense affirmative short form since all you do is change the て/で of te-form to た/だ. Here are some examples.
| Dictionary | Te-Form | Short Form |
| たべる | たべて | たべた |
| よむ | よんで | よんだ |
| あそぶ | あそんで | あそんだ |
| およぐ | およいで | およいだ |
| とる | とって | とった |
Past Negative
I am going to be honest, this one is a bit more complicated, only because it requires a bit more thought. Since negative requires a bit more of a process here it is broken into steps.
General Steps
- Get the dictionary form of the word
- Short form present tense negative conjugate it
- Drop the い
- Add the かった
Steps in Use
- よむ
- よまない
- よまな
- よまなかった
| Dictionary | Present Negative | Short Form |
| たべる | たべない | たべなかった |
| あそぶ | あそばない | あそばなかった |
| およぐ | およがない | およがなかった |
| とる | とらない | とらなかった |
It is still simple, but just have to think it through a bit more. With some practice you can easily get it down.
Note: I keep mentioning knowing the u and ru-verbs and how to distinguish them. I keep bringing this up because it is very important and makes life easier if you understand.
Seems like i have stumbled upon a site that teaches me before the teacher does!
I hope it has helped. We have gone over this in my class, but before I can actually understand it I usually have to sit down and break it down like I did in the post.
If you need help let me know i’ll try to help.