べきだ・
"Should" as a judgment: this is the right thing to do. It is stronger than advice, and it is not a rule. It is what the person saying it believes is right.
should
Experts should honestly admit what they don't know.
should not
You shouldn't laugh at other people's mistakes.
should have
I should have seen a doctor sooner.
How to form it
Verb in the dictionary form + べきだ／べきです
する is するべき or すべき. Both are said; すべき is a little more formal. Past: べきだった.
Should not
Verb in the dictionary form + べきではない
The verb stays positive: 行くべきではない, not 行かないべきだ. In conversation, べきじゃない.
Before a noun
…べき + noun
やるべきこと, "what needs doing".
How strong it is
べきだ appeals to what is right: duty, fairness, good sense. That makes it the natural way to give an opinion about people in general, and newspapers, debates and essays are full of it.
People in positions of responsibility should listen to criticism too.
Companies should take their effect on the environment more seriously.
The same apology at three strengths:
You'd better apologize soon.
Advice. Things will go better for you.
You should apologize soon.
A judgment. It is the right thing to do.
You have to apologize soon.
No choice. A rule or the situation demands it.
Said to someone's face
Said straight to a person, it tells them what is right. Unasked, that is heavy: when all you mean is a friendly tip, it comes out as a sermon, and it is not something to say to a teacher or a boss. と思います makes it your opinion.
One of my staff keeps making the same mistake.
I think you should hear what they have to say first.
Should have: べきだった
About the past it is regret, or blame: the right thing was not done. ばよかった only wishes things had gone differently. べきだった says what was right, so it suits owning up to a mistake.
I should have been more honest then.
I should have reported it sooner. I'm very sorry.
We shouldn't have rushed to a conclusion when the evidence was so thin.
Three phrases you'll hear
やるべきことthings to get done
I have a lot to get done today.
べきかどうかwhether I should
I can't decide whether I should quit my job.
絶対…べきyou really must
You have to see this movie.
Between friends, a warm recommendation and not a sermon.
Close neighbours
たほうがいいN5
The everyday "you should" between friends: this choice is the better one.
It will rain tomorrow, so you should take an umbrella.
なければならないN5
"Must": a rule, or something you can't get out of.
In the library, you must turn off your cell phone.
はずだN4
English "should" as what you expect: "it should arrive at ten". That is はず, not べき.
According to the schedule, the train should arrive at ten.
ばよかったN4
"I wish I had": the everyday sigh over your own past.
I wish I had gone to bed earlier last night.
ことだN3
Advice from someone who knows better, usually practical: what works.
If you want to get better, the thing to do is practice out loud every day, even just a little.
Check yourself
1"You shouldn't say things like that."
そんな
Choose an answer to see why.
2The office rule is that everyone is in by nine. Which one states the rule?
Choose an answer to see why.
3"The parcel should arrive tomorrow."
Choose an answer to see why.
More detail
With an adjective or a noun
It needs ある: …くあるべきだ, …であるべきだ. Mostly written.
A teacher should be fair.
More sentences
You shouldn't judge someone on a single failure.
You shouldn't spread information that has nothing behind it.
The person in charge should report the awkward facts honestly too.
The problem to tackle first right now is the housing shortage.
This is something everyone should think about together.