Mastering Japanese Verb Plain Forms, ない-form & た-form Endings
Welcome to one of the most powerful areas of GCSE Japanese grammar! In this chapter, you will learn how to form plain negative (ない-form) and plain past (た-form) verbs, and attach key grammar patterns to them. Mastering these will immediately boost your ability to give advice, list your weekend activities, describe personal experiences, and understand everyday polite instructions in your Listening, Speaking, Reading, and Writing exams (Papers 1–4).
Don't worry if verb conjugations feel like a lot to take in at first. We will break every step down into clear, logical patterns that are easy to remember.
---Part 1: The Three Verb Groups & Base Conjugations
Before attaching endings, you must know how to conjugate dictionary-form verbs into their ない-form (plain negative) and た-form (plain past) bases. Every Japanese verb belongs to one of three groups.
1. Group 1: Consonant-stem / U-verbs (五段動詞 - Godan)
These verbs end in an -u syllable in their dictionary form (e.g., 書く kaku, 飲む nomu, 買う kau, 待つ matsu).
How to make the ない-form: Change the final -u vowel sound to its matching -a vowel sound, then add ない.
• 書く (kaku) \(\rightarrow\) 書かない (kakanai - do not write)
• 飲む (nomu) \(\rightarrow\) 飲まない (nomanai - do not drink)
• 話す (hanasu) \(\rightarrow\) 話さない (hanasanai - do not speak)
• Special Rule: For verbs ending in single う (-u), change う to わ (wa), NOT あ!
Example: 買う (kau) \(\rightarrow\) 買わない (kawanai - do not buy).
How to make the た-form: Follow the exact same sound-change rules as the て-form, but use た/だ instead of て/で:
• -ku: 書く \(\rightarrow\) 書いた (kaita) (Exception: 行く \(\rightarrow\) 行った / itta)
• -gu: 泳ぐ \(\rightarrow\) 泳いだ (oyoida)
• -su: 話す \(\rightarrow\) 話した (hanashita)
• -tsu, -u, -ru: 待つ \(\rightarrow\) 待った (matta); 買う \(\rightarrow\) 買った (katta); 帰る \(\rightarrow\) 帰った (kaetta)
• -mu, -bu, -nu: 飲む \(\rightarrow\) 飲んだ (nonda); 遊ぶ \(\rightarrow\) 遊んだ (asonda); 死ぬ \(\rightarrow\) 死んだ (shinda)
2. Group 2: Vowel-stem / Ru-verbs (一段動詞 - Ichidan)
These verbs end in -iru or -eru (e.g., 食べる taberu, 見る miru, 起きる okiru).
• ない-form: Drop the る and add ない \(\rightarrow\) 食べる \(\rightarrow\) 食べない (tabenai); 見る \(\rightarrow\) 見ない (minai)
• た-form: Drop the る and add た \(\rightarrow\) 食べる \(\rightarrow\) 食べた (tabeta); 見る \(\rightarrow\) 見た (mita)
3. Group 3: Irregular Verbs (不規則動詞)
There are only two main irregular verbs you must memorise directly:
• する (to do): ない-form = しない (shinai) | た-form = した (shita)
• 来る / くる (to come): ない-form = こない / 来ない (konai) | た-form = きた / 来た (kita)
• Useful Inanimate Verb: ある (to exist): ない-form = ない (nai) | た-form = あった (atta)
Key Takeaway for Part 1: Always identify your verb group first. Group 2 drops る, Group 1 changes the ending sound, and Group 3 must be memorised by heart.
---Part 2: Grammar Endings with ない-form
Once you have formed the ない-form, you can use it to make polite negative requests and give negative advice.
1. Negative Requests: Verb [ない-form] + でください ("Please do not...")
Use this structure when asking someone politely to refrain from doing an action.
Formation: [Verb ない-form] + でください
• この部屋に入らないでください。
Kono heya ni hairanaide kudasai.
(Please do not enter this room.)
• ここで写真を撮らないでください。
Koko de shashin o toranaide kudasai.
(Please do not take photos here.)
• 忘れないでください。
Wasurenaide kudasai.
(Please do not forget.)
2. Negative Advice: Verb [ない-form] + ほうがいいです ("It is better not to...")
Use this structure when advising someone against doing something.
Formation: [Verb ない-form] + ほうがいいです
• それは食べないほうがいいです。
Sore wa tabenai hō ga ii desu.
(You had better not eat that / It is better not to eat that.)
• 夜遅くまで起きないほうがいいです。
Yoru osoku made okinai hō ga ii desu.
(It is better not to stay up late at night.)
• 無理をしないほうがいいです。
Muri o shinai hō ga ii desu.
(It is better not to push yourself too hard / overdo it.)
Key Takeaway for Part 2: Keep the full ない intact before adding でください (requests) or ほうがいいです (advice).
---Part 3: Grammar Endings Derived from た-form
The た-form is used for several high-scoring GCSE grammar patterns.
1. Listing Representative Actions: Verb [た-form] + り、Verb [た-form] + り します
Use this to list a few examples of actions you do/did among other things, without listing every single thing in strict chronological order.
Formation: [Verb 1 た-form] + り、[Verb 2 た-form] + り します / しました
• 買い物をしたり、映画を見たりします。
Kaimono o shitari, eiga o mitari shimasu.
(I do things like shopping and watching films.)
• 週末は本を読んだり、音楽を聞いたりしました。
Shūmatsu wa hon o yondari, ongaku o kiitari shimashita.
(On the weekend, I did things like reading books and listening to music.)
Golden Rule: The tense and politeness are determined entirely by the final します (present/habitual) or しました (past).
2. Expressing Sequence: Verb [た-form] + 後で ("After doing...")
Use this pattern to clearly explain that one action happens directly after another action is completed.
Formation: [Verb た-form] + 後で (あとで)、[Clause 2]
• 勉強をした後で、あそびに行きます。
Benkyō o shita ato de, asobi ni ikimasu.
(After studying, I will go out to play.)
• 晩ご飯を食べた後で、お風呂に入りました。
Ban-gohan o tabeta ato de, ofuro ni hairimashita.
(After eating dinner, I took a bath.)
Note: With verbs, link the た-form directly to 後で. If you use a noun, you need の (e.g., レッスンの後で - after the lesson).
3. Expressing Past Experience: Verb [た-form] + ことがあります ("Have had the experience of...")
Use this pattern to talk about things you have (or have never) done in your lifetime.
Formation: [Verb た-form] + ことがあります / ありません
• 日本へ行ったことがあります。
Nihon e itta koto ga arimasu.
(I have been to Japan.)
• 寿司を食べたことがありません。
Sushi o tabeta koto ga arimasen.
(I have never eaten sushi.)
4. Affirmative Advice: Verb [た-form] + ほうがいいです ("It is better to...")
Use this structure to give a direct, helpful recommendation or piece of advice to do something.
Formation: [Verb た-form] + ほうがいいです
• 薬を飲んだほうがいいです。
Kusuri o nonda hō ga ii desu.
(You had better take some medicine / It is better to take medicine.)
• 早く寝たほうがいいです。
Hayaku neta hō ga ii desu.
(It is better to go to bed early.)
Key Takeaway for Part 3: Affirmative advice takes た-form (nonda hō ga ii), while negative advice takes ない-form (nomanai hō ga ii). Do not mix them up!
---Part 4: Examiner Pitfalls & Common Mistakes
Avoid these common errors highlighted in Edexcel GCSE examiner reports:
1. Mixing up Affirmative Advice:
• Incorrect: ✕ 飲むほうがいいです
• Correct: ○ 飲んだほうがいいです (Affirmative advice strictly requires the た-form).
2. Forgetting the ending します / しました in 〜たり〜たり lists:
• Incorrect: ✕ 本を読んだり、音楽を聞いたり。
• Correct: ○ 本を読んだり、音楽を聞いたりします / しました。 (A sentence cannot end on just たり).
3. Confusing 〜たり〜たり with 〜て〜て:
• Use 〜て、〜て for a chronological, step-by-step order ("I woke up, ate breakfast, then left").
• Use 〜たり、〜たりします for non-exhaustive examples of what you do/did ("I did things like reading and listening to music").
4. Inserting extra particles where they do not belong:
• Incorrect: ✕ 食べたのあとで / ✕ 行ったのことがあります
• Correct: ○ 食べた後で / ○ 行ったことがあります (The plain た-form attaches directly!).
5. Irregular / U-verb Conjugation Slips:
• 買う \(\rightarrow\) ○ 買わない (NOT ✕ 買あない)
• 来る \(\rightarrow\) ○ こない / きた (NOT ✕ くらない / ✕ くりた)
• 行く \(\rightarrow\) ○ 行った (NOT ✕ いいた)
Quick Summary Checklist
• Negative Request: Verb [ない-form] + でください (Please don't...)
• Negative Advice: Verb [ない-form] + ほうがいいです (It's better not to...)
• Affirmative Advice: Verb [た-form] + ほうがいいです (It's better to...)
• Sample Activities: Verb [た]り、Verb [た]り します (Doing things like A and B)
• Time Sequence: Verb [た-form] + 後で (After doing...)
• Life Experience: Verb [た-form] + ことがあります (Have had the experience of...)