Conditionals
I am going to use A and B to refer to the parts of a sentence before and after a conditional in this pattern:
A Conditional B
たら
When A, then B
- Emphasizes statement after it
- General When or If verb form. It is used most of the time
- A must be completed before B
- Non-General facts type statements, i.e. Statements about this time or a particular occurrence. (see ば)
- だったら and でしたら are the same as なら
Usages
- When
- 本をよんだら、返して – Return the book when you have read it
- If (Non past only)
- おにぎりがあったら買う – If they have onigiri, I will buy it.
- 朝3時におきたら眠い – I’m sleepy if I wake up at 3 in the morning
- お金があったらいい – It’s ok if you have money.
- When (Past tense)
- Cause: 窓を開けたら、寒くなった – When I opened the window, it got cold
- Surprise: 窓を開けたら、猫がはいってきた – When I opened the window, a cat came in.
- While (Progressive tense たら, past tense final verb)
- 買い物をしていたら、友達に会った – While I was shopping, I met my friend.
ば
If A, then B (Good thing)
- Places more emphasis on the statement before ば. Stresses IF
- Tends to be used for good results
- General facts or statements that are true every time. (IF a, this is what happens)
- Tends to replace たら for scientific or objective statements.
Usages
- Good things/Should do (Present tense)
- すればいい – It’s good if you do it.
- 聞けばわかる – You’ll understand If you listen/ask.
- 見ればわかる – You’ll understand if you look.
- Should have done A (Past tense)
- 聞けばよかった – If I had asked, it would have been good.
- 知らなければよかった – It would have been better to not know.
- あればたすかった – It would have saved me (some trouble, etc) if I had one.
- General facts (Not limited to one example, area, person)
- 水が氷れば、石をも砕ける – If water freezes, it can even crack rock.
- 人が集まれば、人混みになる – If people gather, it will become a crowd.
と
If X, then of course Y
- と implies a natural consequence.
- Usually inevitable, unavoidable, or definite
- May be a subjective opinion about a natural or obvious result.
- Tends to be used for things that happen quickly afterwards. (verbs)
- Makes surprise statements, not conditional statements about the past.
Usages
- Of course
- グラスを落とすと、割れる – If you drop a glass, it will break.
- 先生だと、あたまがいいはずだ – If they’re a teacher, of course they should be smart.
- Of course its good (といい）
- やさいを食べると体にいい – if you eat your vegetables, of course its good for your body.
- のむといいよ – If you drink it, of course something good will happen (taste) (It’s good!)
- Past tense (Surprise)
- 彼が飲むと、すぐにふきだした – As soon as he drank it, he spit it up.
- ドアを開けると、クマが出てきた – When I opened the door, a bear came out.
- Soon After
- よこになると、子供が泣き出した – When (as soon as) I laid down, (my) kid started crying.
- 食べるとすぐお腹が痛くなる – As soon as I eat it, my stomach starts to hurt.
なら
In A’s case, B
- なら treats some fact (A) as true.
- なら is typically used in response to someone else’s statement.
- B may occur before A is performed.
- ならば means the same thing.
Usages
- Hypothetical situations
- 日本にいくなら、日本語を勉強しないといけない – If you are going to Japan, you need to study Japanese.
- Responding to new information someone else tells you
- それならよかった – If that’s the case, that’s good.
- やったなら問題はない – If you did it, there’s no problem. (possibly doubtful)
- Emphasizing a specific situation
- 彼なら大丈夫 – If it’s him, it’ll be ok.
- When B (statement after なら) will happen before A (reverse order)
- 食べるなら、まずは手を洗う – If you’re going to eat, wash your hands first
- 走るなら、先にストレッチする – If you’re going to run, stretch first
- トイレに行くなら言うな – If you’re going to the bathroom don’t say it.
*Since なら can be in either order, the order may sometimes be vague. Usually a word like まず or context will clue you in.