Drop the final -u from the plain form of the verb and add -eba. To form the negative, drop the -i from the negative plain form and add -kereba. With -i adjectives, drop the final -i and add -kereba; with negatives, drop the final -i from nai and add -kereba.
もしできれば、今年外国へ行きたいんです。
Moshi dekireba, kotoshi gaikoku e ikitai n desu.
If I can, I want to go abroad this year.
辞書を使わなければ、この日本語の宿題ができません。
Jisho o tsukawanakereba, kono Nihongo no shukudai ga dekimasen.
If I don’t use a dictionary, I can’t do this Japanese homework.
明日天気がよければ、どこかへ行きましょうか。
Ashita tenki ga yokereba, dokoka e ikimashou ka.
If the weather’s nice tomorrow, shall we go somewhere?
高くなければ、買います。
Takaku nakereba, kaimasu.
If it’s not too expensive, I’ll buy it.
Using conditionals to express obligation
The expression -nakereba narimasen, where naru is the verb “to become”, means literally “if you don’t…, it’s no good” or in other words “you must” or “you have to”. The negative “don’t have to …” is expressed with -nakute mo ii desu.
自己紹介は日本語でなければなりません。
Jiko shoukai wa Nihongo de nakereba narimasen.
Your self-introduction must be in Japanese.
今日終らなくてもいいです。
Kyou owaranakute mo ii desu.
You don’t have to finish it today.
Past conditionals
もし時間があったら、あのテストは満点だったのに。
Moshi jikan ga attara, ano tesuto wa manten datta noni.
If I’d had enough time, I would have gotten a perfect score on the exams.
もしあの時ピザを食べなかったら、彼女にプレゼントを変えたのに。
Moshi ano toki piza o tabenakattara, kanojo ni purezento o kaeta noni.
If I hadn’t eaten pizza (at) that time, I could have bought gifts for my girlfriend.
This page is a part of “Some Notes on Japanese Grammar” published for your personal use, with the kind permission of Keith Smillie (http://www.cs.ualberta.ca/~smillie/). The section on past conditionals was added by Shizu-san.
Related posts:
7:23 am on November 30th, 2011
変えた ー＞ 買えた
changed -> could have bought
2:49 pm on February 18th, 2010
ah right! I can understand better now,thank you!
4:32 pm on February 17th, 2010
shishimaru-san,
The forms used in the examples above consist of the plain past form of the verb plus the ending ら (ra). This is sometimes referred to as the “~tara” conditional.
I agree with you that there is not enough explanation on this page. I recommend using Tae Kim’s explanations of various conditional forms instead. This can be found at:
http://www.guidetojapanese.org/learn/grammar/conditionals
12:28 pm on February 17th, 2010
i haven’t understand tha past conditional,too. there’s no explanation
1:36 am on April 20th, 2009
3)- bcos most of my questions r really short. i remembered after i posted that last 1
1:29 am on April 20th, 2009
i’m being stubborn…lol. what i dun understand is what do i drop and/or add to verbs(?) to make the p.c?? it doesn’t seem 2 make it 2 my head.
ps-i put my questions here bcos 1) i’m using psp, not enough memory 2 open 2 tabs 4 forum -2) i tend 2 4get what i want 2 ask -3) i 4got what is #3.
so u c tonysan , i hav a very … unpredictable -bad? not sure which- memory. ぐめなさい…..
11:37 am on April 14th, 2009
Alynne-san, please ask a question in the forum and say a little bit more about what it is you don’t understand.
4:48 pm on April 13th, 2009
i dun understand the past conditionals .
6:16 pm on March 7th, 2009
Alien_vs_Me-san, I am only a lower intermediate level student, so anything I wrote for you would have a good chance of being wrong. I’ll take a look in the Tanaka sentence examples for sentences of this type, and post some in the forum if I find any.
By the way, I reread this page, and it already explains how to form the negative conditional better than I did– take any negative form ending in “nai” (verb or adjective) and replace the “i” by “kereba”, so that the ending is now “nakereba”; tatoeba omoshirokunai->omoshirokunakereba, mitsukenai->mitsukenakereba, kakanai->kakanakereba.
4:54 pm on March 7th, 2009
Tony-san, could you write few sample sentences with ~eba past past neg. please?
4:22 pm on March 7th, 2009
For adjectives, the negative conditional is -kunakereba; tatoeba, “takakunakereba” = “if (it) isn’t high/expensive”.
For verbs, the negative conditional is formed by changing the -nai of the plain past to -nakereba; tatoeba, “tabenakereba” = “if (one) doesn’t eat”, “kakanakereba” = “if (one) doesn’t write”.
The -tara forms may be what you are looking for when you ask for past conditionals; but I think they don’t correspond in usage exactly with past conditional forms in English.
With na adjectives and nouns, I believe you use conditional forms of desu (like “naraba” ); in some cases suru (“sureba” ) or iru (“ireba” ) might be needed instead.
1:50 pm on March 7th, 2009
I wanted to know, what is the -eba- and -kereba- past and past negative verb and i adject. gram case.
And what is with na adject.