In GENKI Lesson 12, you’ll learn key grammar patterns that allow you to give advice, express obligation (“must do”), and warn someone about going too far (“too much”). Mastering these will help you offer practical suggestions and warnings in any situation.
Giving Advice: 「〜ほうがいいです」 (hou ga ii desu)
To give advice or suggest that something is “better to do” or “should do,” you use the 「〜ほうがいいです」 pattern.
The verb form that comes before 「ほうがいいです」 must be the short form.
| Advice | Verb Form | Structure | Example |
| Positive Advice (Should do) | Past Short Form (〜た) | 〜た ほうがいいです | 薬を飲んだほうがいいです。 (Kusuri o nonda hou ga ii desu.) You should take medicine. |
| Negative Advice (Should not do) | Negative Short Form (〜ない) | 〜ない ほうがいいです | お酒を飲まないほうがいいです。 (Osake o nomanai hou ga ii desu.) You shouldn’t drink alcohol. |
Key Point: Even for positive advice (“should do”), you use the past tense short form (〜た). This is a common point of confusion for beginners, so remember the Verb（ta）+ほうがいい structure!
Expressing Obligation: 「〜なければいけません」 (nakereba ikemasen)
To express a strong obligation or necessity—meaning you “must do” or “have to do” something—you use the 「〜なければいけません」 pattern.
The verb form that comes before 「なければいけません」 is the short negative stem (the form before ない).
- Verb Negative Stem + なければいけません
| Verb Form | Example | Meaning |
| 行かない → 行かなければいけません | 宿題をしなければいけません。 (Shukudai o shinakereba ikemasen.) | I must do my homework. |
| たべない → たべなければいけません | 毎日野菜を食べなければいけません。 (Mainichi yasai o tabenakereba ikemasen.) | I have to eat vegetables every day. |
Common alternative: A slightly less formal but very common way to express obligation is 「〜なきゃいけません」 (nakya ikemasen).
Warning About Extremes: 「〜すぎる」 (sugiru)
To warn someone that they are doing something “too much” or that something is “too [adjective],” you use the suffix 「すぎる」 (sugiru). This verb is always conjugated as a Group 2 (-ru) verb.
| Word Type | Rule | Example | Meaning |
| Verbs | Drop -masu and add すぎる | 食べすぎます。 (Tabesugimasu.) | I eat too much. |
| い-Adjectives | Drop い and add すぎる | この部屋は広すぎます。 (Kono heya wa hirosugimasu.) | This room is too spacious. |
| な-Adjectives | Drop な and add すぎる | これは有名すぎます。 (Kore wa yuumeisugimasu.) | This is too famous. |
Putting it Together: Making Suggestions
By combining these patterns, you can give well-rounded advice:
・You should not eat too much candy, because you must take care of your health.
お菓子を食べすぎないほうがいいです。 健康に気をつけなければいけませんから。
(Okashi o tabesuginai hou ga ii desu. Kenkou ni ki o tsukenakereba ikemasen kara.)
・It’s too cold today, so you should wear a coat. 今日は寒すぎる から、 コートを着たほうがいいです。 (
Kyou wa samusugiru kara, kōto o kita hou ga ii desu.)
・Since the store is too expensive, you shouldn’t buy that item. その店は高すぎる ので、 その物を買わないほうがいいです。 (
Sono mise wa takasugiru node, sono mono o kawanai hou ga ii desu.)
・You must submit the homework today, so you should not play games. 宿題を今日出さなければいけません から、 ゲームをしないほうがいいです。 (
Shukudai o kyou dasanakereba ikemasen kara, geemu o shinai hou ga ii desu.)
・You shouldn’t study too much, because you must sleep well. 勉強しすぎないほうがいいです。 よく寝なければいけませんから。 (
Benkyou shisuginai hou ga ii desu. Yoku nenakereba ikemasen kara.)
Now you have the tools to give advice, talk about your duties, and warn others about overdoing things in Japanese!