Japanese grammar · Elementary (A2)
Advice and obligation
Giving advice with ～たほうがいい, saying what you must or don't have to do (～なければならない, ～ないといけない, ～なくてもいい) and should do (～べきだ).
You'd better: ～たほうがいい
To give advice, take the plain past (the た-form) and add (hō ga ii), literally “the side of having done it is good”: (yasunda hō ga ii desu), you'd better rest. For advice not to do something, use the plain negative: (muri shinai hō ga ii desu), you shouldn't overdo it.
～たほうがいい is fairly direct. Add (yo) to sound caring, or (to omoimasu) to soften it. A gentler suggestion is ～たらどうですか (-tara dō desu ka), why don't you …?, in casual speech ～たら？ (-tara?).
- 今日は早く寝たほうがいいですよ。Kyō wa hayaku neta hō ga ii desu yo.You'd better go to bed early today.
- 熱があるなら、お風呂に入らないほうがいいです。Netsu ga aru nara, ofuro ni hairanai hō ga ii desu.If you have a fever, it's better not to take a bath.
- 一度、病院に行ったらどう？Ichido, byōin ni ittara dō?Why don't you go and see a doctor?
Must: ～なければならない and ～ないといけない
Japanese says “must” as a double negative: “if I don't do it, it won't do”. Take the plain negative, change ～ない (-nai) to ～なければ (-nakereba), and add (naranai) or (ikenai). Polite: (narimasen), (ikemasen).
～なければならない sounds formal and suits rules and duties; ～なければいけない is a little more personal. In conversation, ～ないといけない (-nai to ikenai) is the most common. Between friends it shrinks to ～なきゃ (-nakya) or ～ないと (-nai to), with the rest left unsaid.
| Form | Style |
|---|---|
| (ikanakereba narimasen) | formal: rules, duties, announcements |
| (ikanakereba ikemasen) | polite |
| (ikanai to ikemasen) | polite, spoken |
| (ikanai to ikenai) | plain, spoken |
| (ikanakya) | casual |
| (ikanai to) | casual |
- 次の駅で乗り換えなければなりません。Tsugi no eki de norikaenakereba narimasen.You have to change trains at the next station.
- 毎日、薬を飲まないといけません。Mainichi, kusuri o nomanai to ikemasen.I have to take medicine every day.
- もう八時だ。帰らなきゃ。Mō hachiji da. Kaeranakya.It's already eight. I've got to go home.
Don't have to: ～なくてもいい
To say something isn't necessary, change ～ない (-nai) to ～なくても (-nakute mo) and add (ii): (konakute mo ii desu), you don't have to come. (daijōbu desu) instead of sounds friendly and reassuring.
Don't mix it up with ～てはいけない (-te wa ikenai), which means “must not”: (koko de shashin o totte wa ikemasen), you must not take photos here.
- 明日は会社に来なくてもいいですよ。Ashita wa kaisha ni konakute mo ii desu yo.You don't have to come to the office tomorrow.
- 切符は買わなくても大丈夫です。Kippu wa kawanakute mo daijōbu desu.You don't need to buy a ticket.
Should: ～べきだ (B2)
(beki da) after the dictionary form means “should” in the sense of duty or what is right: (yakusoku wa mamoru beki da), you should keep your promises. With (suru), (subeki) is common, and (suru beki) is also used. The negative is ～べきではない (beki de wa nai), should not; the past ～べきだった (beki datta), should have.
is strong and a little moralising. It suits debates, opinions about society and regrets about yourself. For personal advice to someone, ～たほうがいい is kinder. In a discussion, soften it: ～べきではないでしょうか (beki de wa nai deshō ka), shouldn't we …?
- この問題はみんなで話し合うべきだと思います。Kono mondai wa minna de hanashiau beki da to omoimasu.I think we should all discuss this problem together.
- 住民の意見をもっと聞くべきではないでしょうか。Jūmin no iken o motto kiku beki de wa nai deshō ka.Shouldn't we listen more to what residents think?
- もっと早く相談すべきだった。Motto hayaku sōdan subeki datta.I should have asked for advice sooner.