Past tense with でした

～でした ~ deshita Was; were

でした (deshita) is the past of です: "A was B". One form covers was and were, so English agreement and articles still need work.

Level: JLPT N5, beginner
Type: Sentence basics
English links: past of be, was and were, articles

What it means

でした is the past form of です. 昨日は日曜日です sounds odd, because yesterday is over. 昨日は日曜日でした is right: "Yesterday was Sunday". You only change the end of the sentence.

It is the same for every subject. "I was", "he was" and "they were" all use でした. The plain form, with friends, is だった.

One trap for us as learners: でした goes after nouns and な-adjectives, like 静かでした. It does not go after い-adjectives. 高かったです is right, and 高いでした is a mistake that many English speakers make.

You will sometimes hear でした when English would use the present, to check something you knew before: お名前は何でしたか (What was your name again?). English does the same thing, so this one is easy to explain.

How to build it

Pattern	How it works
A は B でした A wa B deshita	Polite past. The same for every subject.
A は B だった A wa B datta	The plain past, with friends and family.
静か → 静かでした shizuka → shizuka deshita	な-adjectives take でした too.
高い → 高かったです takai → takakatta desu	い-adjectives have their own past. Not 高いでした.

Examples

昨日は日曜日でした。 kinou wa nichiyoubi deshita. Yesterday was Sunday.
父は数学の先生でした。 chichi wa suugaku no sensei deshita. My father was a maths teacher.
中学生のとき、野球部でした。 chuugakusei no toki, yakyuubu deshita. I was in the baseball club in junior high.
テストは先週でした。 tesuto wa senshuu deshita. The test was last week.
昨日は雨でした。 kinou wa ame deshita. It rained yesterday.

How English says it

English uses "was" and "were". "I", "he", "she" and "it" take "was". "You", "we" and "they" take "were". This is the only past verb in English that changes with the subject.

English also changes the sentence shape more than Japanese does. 雨でした is "it rained" or "it was rainy", not "was rain". 野球部でした is "I was in the baseball club", with "in".

Why it can make English hard

でした is one form, so was and were get mixed up. "My grandparents was farmers" is a common error.
Japanese uses でした with nouns where English needs a verb or a preposition. 雨でした and 野球部でした come out as "Yesterday was rain" and "I was baseball club".
The article problem from A は B です comes back in the past: "When I was child".

Mistakes you will hear

Yesterday was rain. It rained yesterday. (or It was rainy yesterday.) A word-for-word 昨日は雨でした. English uses the verb "rain" or the adjective "rainy".
I was baseball club. I was in the baseball club. You are a member of a club, so English needs "in".
My grandparents was farmers. My grandparents were farmers. でした is the same for every subject. English "be" is not.
When I was child, I lived in Osaka. When I was a child, I lived in Osaka. The missing article again.

In the classroom

Bring old photos, or use your own. Students say what people were: "She was a student. They were in a band." Was and were come up naturally.
Ask "What club were you in?" around the class. Write the answers on the board with "in" underlined. Club talk is a strong topic in Japanese schools.
Make a weather diary for last week: "It was sunny on Monday. It rained on Tuesday." Students see that rain can be a verb.

Practice

Try each one, then open it to check.

1. Fill the gap: 昨日は休み＿。 (Yesterday was a day off.)

Answer: でした

It is in the past, so です becomes でした.
2. Translate: 母は医者でした。

Answer: My mother was a doctor.

Use "was" for "my mother", and "a" before the job.
3. A student writes "My brothers was in the soccer club." Fix it.

Answer: My brothers were in the soccer club.

"Brothers" is plural, so it takes "were".
4. You write 試験は難しいでした。 Fix it.

Answer: 試験は難しかったです。

難しい is an い-adjective. It makes its own past with かった, not でした.