Hey, you.

Have you been studying? You'd better be!

Sorry, maybe that advice was a bit too forceful.

I was out of line.

But yeah, we should study. And I mean that "should" in a strong, forceful way. Almost like it's our obligation to study.

Speaking of obligations (and this is not actually a coincidence at all, by the way), today's grammar point, べきだ, means "should."

JLPT N3: べきだ (should)

べきだ attaches to verbs in the plain present tense. In other words, our formation is:

V る ＋ べきだ

行くべきだ（いくべきだ // should go）
挑戦するべきだ（ちょうせんするべきだ // should try; should challenge [oneself]）

However!

Sometimes する specifically will be shortened to just す-, giving us すべきだ.

Specifically, we'll see:

廃止すべきだ（はいしすべきだ // should be discontinued）

Also note that we can have the more formal べきです instead of べきだ.

We can even have a negative copula, as in this example:

与えるべきではない（あたえるべきではない // should not give）

ではない is one of the negative forms of だ.

Now let's see べきだ in action!

Action, action, we want action!

We can use it to give (strong / forceful) advice, like in this sentence:

39度の熱がある？そりゃ、今すぐ病院に行くべきだよ。
さんじゅうきゅう　ど　の　ねつ　が　ある？　そりゃ、　いますぐ　びょういん　に　いくべきだよ。
You have a 39 degree fever? You should go to the hospital right away, then.
Literally: “39 degrees + の + fever + が + have? + then, + right away + hospital + に + go + べきだ + よ.”

What about ～た方がいい (～たほうがいい), which is another way to form "should" sentences?

(Note that we'll look at ～た方がいい in an N4 lesson.)

Well, べきだ is more forceful than ～た方がいい.

That is to say, you should not use べきだ for advice that is given lightly.

We use べきだ to give advice strongly or to talk about obligations.

Aside from giving personal advice, we can also use べきだ to talk about general obligations, as in the following three examples:

何歳になっても、新しいことに挑戦するべきです。
なんさい　に　なっても、　あたらしい　こと　に　ちょうせん　するべきです。
No matter how old you get, you should still try new things.
Literally: “what age + に + even if (you) become, + new + thing + に + challenge + do + べきです.”

わたしはすべての原子力発電所を廃止すべきだと考えています。
わたし　は　すべて　の　げんしりょくはつでんしょ　を　はいし　すべきだ　と　かんがえています。
In my opinion, all nuclear power plants should be shut down.
Literally: “I + は + all + の + nuclear power plants + を + discontinuance + すべきだ + と + am thinking.”

動物には、人間の食べ物を与えるべきではない。
どうぶつ　に　は、　にんげん　の　たべもの　を　あたえるべきではない。
You shouldn’t give human food to animals.
Literally: “animals + には, + human + の + food + を + give + べきではない.”

Note, however, that we cannot use べきだ for rules, laws, procedures, etc.

In other words, it can be used as a strong "should," but it cannot mean "must." Consequently, the following sentence is incorrect:

× 獣医になるには、免許をとるべきだ。
× じゅうい　に　なる　に　は、　めんきょ　を　とるべきだ。
× To become a veterinarian, you should get a license.
× Literally: “veterinarian + に + become + には, + license + を + take + べきだ.”

Instead, we'd have to use a different grammatical formation, like ～なければならない (which we'll look at in another lesson):

○ 獣医になるには、免許をとらなければならない。
○ じゅうい　に　なる　に　は、　めんきょ　を　とらなければならない。
○ To become a veterinarian, you must get a license.
○ Literally: “veterinarian + に + become + には, + license + を + must take.”

That's all for this one. It might not look too hard in isolation.

The trick, rather, is figuring out which grammatical form we use for "should," "must," etc. when speaking Japanese.

This isn't something that you'll know right away--first we need to look at all of the possibilities! (Most of these types of grammatical formations will be covered in N4 and N3 lessons, by the way.)