Lesson 21
Past Tense: Talking About Yesterday
Talking About Past Time: Key Vocabulary
To describe things that happened yesterday or in the past, you first need the vocabulary for past time frames. In Japanese, the most common word for yesterday is きのう (kinou, 昨日). Other helpful related terms include おととい (ototoi, the day before yesterday), けさ (kesa, this morning), and ゆうべ (yuube, last night) or さくばん (sakuban, last night).
An essential grammatical rule for Japanese time expressions is that relative time words do not take the particle に (ni). Absolute time words like 'at 3 o'clock' (さんじに / 3-ji ni) or 'on Monday' (げつようびに / getsuyoubi ni) require に, but relative words like きのう (yesterday), きょう (today), and あした (tomorrow) are used directly as sentence topics or adverbs without に. For example, you say 'きのう、本を読みました' (Kinou, hon o yomimashita - Yesterday, I read a book), not 'きのうに'.
Polite Past Affirmative Verbs: 〜ました (-mashita)
In earlier lessons, you learned that polite non-past verbs end in 〜ます (-masu). This form covers both current habits and future plans. To turn any polite verb into the past affirmative ('did [action]'), simply change the ending 〜ます (-masu) to 〜ました (-mashita). This rule applies consistently to all Japanese verbs in the polite form without irregular exceptions.
For example, the verb 食べます (tabemasu, to eat) becomes 食べました (tabemashita, ate). The verb 行きます (ikimasu, to go) becomes 行きました (ikimashita, went). Consider this complete sentence: きのう、デパートへ行きました (Kinou, depaato e ikimashita - Yesterday, I went to the department store). The object particle を (o), destination particles へ (e) or に (ni), and location particle で (de) maintain their regular functions in past-tense sentences.
Polite Past Negative Verbs: 〜ませんでした (-masendeshita)
To express that you did not do an action in the past, you combine the negative marker 〜ません (-masen) with the past copula でした (deshita), creating the compound ending 〜ませんでした (-masendeshita). This replaces the standard present negative ending and translates to 'did not [verb]'.
Take the verb 勉強します (benkyou shimasu, to study). In the negative past, it becomes 勉強しませんでした (benkyou shimasen deshita, did not study). If you want to say you did not drink coffee this morning, you say: けさ、コーヒーを飲みませんでした (Kesa, koohii o nomimasen deshita). Just like the affirmative past, this conjugation is completely uniform across all verbs once you have their ます-base.
The Past Tense of です: でした and ではありませんでした
When a sentence ends with the polite copula です (desu, 'is/am/are') attached to a noun or な-adjective, you do not use verb endings like ました. Instead, you conjugate です itself into its past forms. The polite affirmative past of です is でした (deshita, 'was/were'). For example, 'きのうは日曜日でした' (Kinou wa nichiyoubi deshita - Yesterday was Sunday).
The polite negative past for nouns and な-adjectives is じゃありませんでした (ja arimasen deshita) in spoken Japanese, or the slightly more formal ではありませんでした (dewa arimasen deshita). For example: きのうは休みではありませんでした (Kinou wa yasumi dewa arimasen deshita - Yesterday was not a day off). Be careful not to confuse this with い-adjectives, which conjugate their stems directly into 〜かったです (-katta desu).
Asking and Answering Questions About Yesterday
To ask someone what they did yesterday, add the question particle か (ka) to the past tense verb. A very common conversational question is: きのう、何をしましたか (Kinou, nani o shimashita ka - What did you do yesterday?). The verb しました (shimashita) is the past tense of します (shimasu, to do).
When answering, you can state your action directly, such as '映画を見ました' (Eiga o mimashita - I watched a movie). If you did not do anything at all, you use the interrogative pronoun 何 (nani) combined with the emphatic particle も (mo) and a negative past verb: 何もしませんでした (Nani mo shimasen deshita - I didn't do anything). This pattern works similarly with だれ (dare, who): だれにも会いませんでした (Dare ni mo aimasen deshita - I didn't meet anyone).
Lesson quiz · 1 of 5
Which is the correct polite past affirmative form of the verb 買います (kaimasu, to buy)?