The past negative equivalent of the verb ending ます is ませんでした.
わたしは えいごを べんきょうしませんでした。
I didn't study English.
| Affirmative | Negative | |
| Nonpast | かきます | かきません |
| Past | かきました | かきませんでした |
The term "Nonpast" is used instead of "Present" because a verb in this form is not necessarily present in tense, but actually represents imperfect/unfinished conditions which could be present or future.